diff --git a/lib/splitclient-rb/engine/api/client.rb b/lib/splitclient-rb/engine/api/client.rb
index 9ddaf94c..65dcd027 100644
--- a/lib/splitclient-rb/engine/api/client.rb
+++ b/lib/splitclient-rb/engine/api/client.rb
@@ -10,6 +10,7 @@ def initialize(config)
       end
 
       def get_api(url, api_key, params = {}, cache_control_headers = false)
+        api_client.options.params_encoder.sort_params = false
         api_client.get(url, params) do |req|
           req.headers = common_headers(api_key).merge('Accept-Encoding' => 'gzip')
           req.headers = req.headers.merge('Cache-Control' => 'no-cache') if cache_control_headers
@@ -29,7 +30,7 @@ def post_api(url, api_key, data, headers = {}, params = {})
           req.headers = common_headers(api_key)
                         .merge('Content-Type' => 'application/json')
                         .merge(headers)
-          
+
           machine_ip = @config.machine_ip
           machine_name = @config.machine_name
 
@@ -55,6 +56,7 @@ def api_client
         @api_client ||= Faraday.new do |builder|
           builder.use SplitIoClient::FaradayMiddleware::Gzip
           builder.adapter :net_http_persistent
+          builder.options.params_encoder = Faraday::FlatParamsEncoder
         end
       end
 
diff --git a/lib/splitclient-rb/engine/api/splits.rb b/lib/splitclient-rb/engine/api/splits.rb
index 2bcb804c..28a266f9 100644
--- a/lib/splitclient-rb/engine/api/splits.rb
+++ b/lib/splitclient-rb/engine/api/splits.rb
@@ -4,6 +4,9 @@ module SplitIoClient
   module Api
     # Retrieves split definitions from the Split Backend
     class Splits < Client
+
+      SPEC_VERSION = "1.1"
+
       def initialize(api_key, config, telemetry_runtime_producer)
         super(config)
         @api_key = api_key
@@ -11,10 +14,10 @@ def initialize(api_key, config, telemetry_runtime_producer)
         @flag_sets_filter = @config.flag_sets_filter
       end
 
-      def since(since, fetch_options = { cache_control_headers: false, till: nil, sets: nil })
+      def since(since, fetch_options = { cache_control_headers: false, till: nil, sets: nil})
         start = Time.now
 
-        params = { since: since }
+        params = { s: SPEC_VERSION, since: since }
         params[:till] = fetch_options[:till] unless fetch_options[:till].nil?
         params[:sets] = @flag_sets_filter.join(",") unless @flag_sets_filter.empty?
         @config.logger.debug("Fetching from splitChanges with #{params}: ")
diff --git a/lib/splitclient-rb/engine/auth_api_client.rb b/lib/splitclient-rb/engine/auth_api_client.rb
index e0d7a903..b9dcf4ff 100644
--- a/lib/splitclient-rb/engine/auth_api_client.rb
+++ b/lib/splitclient-rb/engine/auth_api_client.rb
@@ -14,7 +14,7 @@ def initialize(config, telemetry_runtime_producer)
 
       def authenticate(api_key)
         start = Time.now
-        response = @api_client.get_api(@config.auth_service_url, api_key)
+        response = @api_client.get_api("#{@config.auth_service_url}?s=#{SplitIoClient::Api::Splits::SPEC_VERSION}", api_key)
 
         return process_success(response, start) if response.success?
 
diff --git a/spec/cache/fetchers/segment_fetch_spec.rb b/spec/cache/fetchers/segment_fetch_spec.rb
index e49c788a..f816f445 100644
--- a/spec/cache/fetchers/segment_fetch_spec.rb
+++ b/spec/cache/fetchers/segment_fetch_spec.rb
@@ -26,7 +26,7 @@
     stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=1473863075059')
       .to_return(status: 200, body: segments_json2)
 
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body: splits_with_segments_json)
   end
 
diff --git a/spec/cache/fetchers/split_fetch_spec.rb b/spec/cache/fetchers/split_fetch_spec.rb
index 2d320734..957d4101 100644
--- a/spec/cache/fetchers/split_fetch_spec.rb
+++ b/spec/cache/fetchers/split_fetch_spec.rb
@@ -11,7 +11,7 @@
   end
 
   before do
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body: active_splits_json)
   end
 
@@ -48,7 +48,7 @@
       active_split = store.splits_repository.splits['test_1_ruby']
       expect(active_split[:status]).to eq('ACTIVE')
 
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1473413807667')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1473413807667')
         .to_return(status: 200, body: archived_splits_json)
 
       store.send(:fetch_splits)
@@ -81,7 +81,7 @@
     let(:store) { described_class.new(splits_repository, '', config, telemetry_runtime_producer) }
 
     before do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_2&since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&sets=set_2')
       .to_return(status: 200, body: active_splits_json)
     end
 
@@ -103,14 +103,14 @@
       expect(store.splits_repository.get_split('sample_feature')[:name]).to eq('sample_feature')
       expect(store.splits_repository.get_split('test_1_ruby')).to eq(nil)
 
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_2&since=1473413807667')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1473413807667&sets=set_2')
         .to_return(status: 200, body: archived_splits_json)
 
       store.send(:fetch_splits)
       expect(store.splits_repository.get_split('sample_feature')).to eq(nil)
 
       store.splits_repository.set_change_number(-1)
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_2&since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&sets=set_2')
         .to_return(status: 200, body: active_splits_json)
 
       store.send(:fetch_splits)
@@ -149,7 +149,7 @@
       active_split = store.splits_repository.splits['test_1_ruby']
       expect(active_split[:status]).to eq('ACTIVE')
 
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1473413807667')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1473413807667')
         .to_return(status: 200, body: archived_splits_json)
 
       store.send(:fetch_splits)
diff --git a/spec/engine/api/splits_spec.rb b/spec/engine/api/splits_spec.rb
index 7850e6db..63e00943 100644
--- a/spec/engine/api/splits_spec.rb
+++ b/spec/engine/api/splits_spec.rb
@@ -18,7 +18,7 @@
     let(:splits_api) { described_class.new('', config, telemetry_runtime_producer) }
 
     it 'returns splits with segment names' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: splits)
 
       parsed_splits = splits_api.send(:splits_with_segment_names, splits)
@@ -41,7 +41,7 @@
     let(:splits_api) { described_class.new('', config, telemetry_runtime_producer) }
 
     it 'returns the splits - with 2 sets param' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_1,set_2&since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&sets=set_1,set_2')
         .with(headers: {
                 'Accept' => '*/*',
                 'Accept-Encoding' => 'gzip',
@@ -61,7 +61,7 @@
     end
 
     it 'raise api exception when status 414' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_1,set_2&since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&sets=set_1,set_2')
         .with(headers: {
                 'Accept' => '*/*',
                 'Accept-Encoding' => 'gzip',
@@ -96,7 +96,7 @@
     let(:splits_api) { described_class.new('', config, telemetry_runtime_producer) }
 
     it 'returns the splits - checking headers when cache_control_headers is false' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .with(headers: {
                 'Accept' => '*/*',
                 'Accept-Encoding' => 'gzip',
@@ -115,7 +115,7 @@
     end
 
     it 'returns the splits - with till param' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1&till=123123')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&till=123123')
         .with(headers: {
                 'Accept' => '*/*',
                 'Accept-Encoding' => 'gzip',
@@ -135,7 +135,7 @@
     end
 
     it 'returns the splits - checking headers when cache_control_headers is true' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .with(headers: {
                 'Accept' => '*/*',
                 'Accept-Encoding' => 'gzip',
@@ -156,7 +156,7 @@
     end
 
     it 'throws exception if request to get splits from API returns unexpected status code' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 404)
 
       expect { splits_api.since(-1) }.to raise_error(
@@ -166,7 +166,7 @@
     end
 
     it 'throws exception if request to get splits from API fails' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_raise(StandardError)
 
       expect { splits_api.since(-1) }.to raise_error(
@@ -175,7 +175,7 @@
     end
 
     it 'throws exception if request to get splits from API times out' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_timeout
 
       expect { splits_api.since(-1) }.to raise_error(
diff --git a/spec/engine/auth_api_client_spec.rb b/spec/engine/auth_api_client_spec.rb
index 096aae2c..0235c130 100644
--- a/spec/engine/auth_api_client_spec.rb
+++ b/spec/engine/auth_api_client_spec.rb
@@ -15,7 +15,7 @@
   let(:telemetry_runtime_producer) { SplitIoClient::Telemetry::RuntimeProducer.new(config) }
 
   it 'authenticate success' do
-    stub_request(:get, config.auth_service_url).to_return(status: 200, body: body_response)
+    stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 200, body: body_response)
 
     auth_api_client = subject.new(config, telemetry_runtime_producer)
     response = auth_api_client.authenticate(api_key)
@@ -26,7 +26,7 @@
   end
 
   it 'auth server return 500' do
-    stub_request(:get, config.auth_service_url).to_return(status: 500)
+    stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 500)
 
     auth_api_client = subject.new(config, telemetry_runtime_producer)
     response = auth_api_client.authenticate(api_key)
@@ -36,7 +36,7 @@
   end
 
   it 'auth server return 401' do
-    stub_request(:get, config.auth_service_url).to_return(status: 401)
+    stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 401)
 
     auth_api_client = subject.new(config, telemetry_runtime_producer)
     response = auth_api_client.authenticate(api_key)
diff --git a/spec/engine/matchers/between_matcher_spec.rb b/spec/engine/matchers/between_matcher_spec.rb
index ba8b980c..9e16e550 100644
--- a/spec/engine/matchers/between_matcher_spec.rb
+++ b/spec/engine/matchers/between_matcher_spec.rb
@@ -43,7 +43,7 @@
 #        .to_return(status: 200, body: number_matcher_splits)
       stub_request(:get, 'https://sdk.split.io/api/splitChanges')
         .to_return(status: 200, body: number_matcher_splits)
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: number_matcher_splits)
       subject.block_until_ready
       sleep 1
@@ -69,7 +69,7 @@
     let(:non_matching_low_value_negative_attributes) { { income: -999 } }
 
     before do
-       stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since.*/)
+       stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since.*/)
         .to_return(status: 200, body: negative_number_matcher_splits)
       subject.block_until_ready
       sleep 1
@@ -97,7 +97,7 @@
     let(:non_matching_high_value_attributes) { { created: 1_459_775_460 } } # "2016/04/04T13:11Z"
 
     before do
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: datetime_matcher_splits)
       subject.block_until_ready
       sleep 1
diff --git a/spec/engine/matchers/combining_matcher_spec.rb b/spec/engine/matchers/combining_matcher_spec.rb
index a602ebbd..bdaccaa7 100644
--- a/spec/engine/matchers/combining_matcher_spec.rb
+++ b/spec/engine/matchers/combining_matcher_spec.rb
@@ -19,7 +19,7 @@
   before do
     stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=-1')
       .to_return(status: 200, body: segments_json)
-    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
       .to_return(status: 200, body: splits_json)
     stub_request(:any, /https:\/\/telemetry.*/)
       .to_return(status: 200, body: 'ok')
diff --git a/spec/engine/matchers/equal_to_matcher_spec.rb b/spec/engine/matchers/equal_to_matcher_spec.rb
index a9daf292..043b39df 100644
--- a/spec/engine/matchers/equal_to_matcher_spec.rb
+++ b/spec/engine/matchers/equal_to_matcher_spec.rb
@@ -37,7 +37,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: 'ok')
@@ -64,7 +64,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: zero_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: 'ok')
@@ -90,7 +90,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: negative_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: 'ok')
@@ -117,7 +117,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
           .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: date_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: 'ok')
diff --git a/spec/engine/matchers/greater_than_or_equal_to_matcher_spec.rb b/spec/engine/matchers/greater_than_or_equal_to_matcher_spec.rb
index 0307dae7..5283bfb9 100644
--- a/spec/engine/matchers/greater_than_or_equal_to_matcher_spec.rb
+++ b/spec/engine/matchers/greater_than_or_equal_to_matcher_spec.rb
@@ -35,7 +35,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
@@ -61,7 +61,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: negative_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
@@ -92,7 +92,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: date_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
diff --git a/spec/engine/matchers/less_than_or_equal_to_matcher_spec.rb b/spec/engine/matchers/less_than_or_equal_to_matcher_spec.rb
index bd53166c..60936dc0 100644
--- a/spec/engine/matchers/less_than_or_equal_to_matcher_spec.rb
+++ b/spec/engine/matchers/less_than_or_equal_to_matcher_spec.rb
@@ -37,7 +37,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
@@ -64,7 +64,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: negative_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
@@ -93,7 +93,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: date_splits_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
@@ -119,7 +119,7 @@
     before do
       stub_request(:any, /https:\/\/telemetry.*/)
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
         .to_return(status: 200, body: date_splits2_json)
       stub_request(:any, /https:\/\/events.*/)
         .to_return(status: 200, body: "", headers: {})
diff --git a/spec/engine/matchers/whitelist_matcher_spec.rb b/spec/engine/matchers/whitelist_matcher_spec.rb
index e2472867..25f4a4ba 100644
--- a/spec/engine/matchers/whitelist_matcher_spec.rb
+++ b/spec/engine/matchers/whitelist_matcher_spec.rb
@@ -22,7 +22,7 @@
   before do
     stub_request(:any, /https:\/\/telemetry.*/)
       .to_return(status: 200, body: 'ok')
-    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
       .to_return(status: 200, body: splits_json)
     stub_request(:any, /https:\/\/events.*/)
       .to_return(status: 200, body: "", headers: {})
diff --git a/spec/engine/push_manager_spec.rb b/spec/engine/push_manager_spec.rb
index 03f2187b..a1a6d9e7 100644
--- a/spec/engine/push_manager_spec.rb
+++ b/spec/engine/push_manager_spec.rb
@@ -43,7 +43,7 @@
           send_mock_content(res, 'content')
         end
 
-        stub_request(:get, config.auth_service_url).to_return(status: 200, body: body_response)
+        stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 200, body: body_response)
         config.streaming_service_url = server.base_uri
 
         sse_handler = SplitIoClient::SSE::SSEHandler.new(config, splits_worker, segments_worker, sse_client)
@@ -51,7 +51,7 @@
         push_manager = subject.new(config, sse_handler, api_key, runtime_producer)
         connected = push_manager.start_sse
 
-        expect(a_request(:get, config.auth_service_url)).to have_been_made.times(1)
+        expect(a_request(:get, config.auth_service_url + "?s=1.1")).to have_been_made.times(1)
 
         sleep(1.5)
         expect(connected).to eq(true)
@@ -61,14 +61,14 @@
     end
 
     it 'must not connect to server. Auth server return 500' do
-      stub_request(:get, config.auth_service_url).to_return(status: 500)
+      stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 500)
 
       sse_handler = SplitIoClient::SSE::SSEHandler.new(config, splits_worker, segments_worker, sse_client)
 
       push_manager = subject.new(config, sse_handler, api_key, runtime_producer)
       connected = push_manager.start_sse
 
-      expect(a_request(:get, config.auth_service_url)).to have_been_made.times(1)
+      expect(a_request(:get, config.auth_service_url + "?s=1.1")).to have_been_made.times(1)
 
       sleep(1.5)
 
@@ -77,14 +77,14 @@
     end
 
     it 'must not connect to server. Auth server return 401' do
-      stub_request(:get, config.auth_service_url).to_return(status: 401)
+      stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 401)
 
       sse_handler = SplitIoClient::SSE::SSEHandler.new(config, splits_worker, segments_worker, sse_client)
 
       push_manager = subject.new(config, sse_handler, api_key, runtime_producer)
       connected = push_manager.start_sse
 
-      expect(a_request(:get, config.auth_service_url)).to have_been_made.times(1)
+      expect(a_request(:get, config.auth_service_url + "?s=1.1")).to have_been_made.times(1)
 
       sleep(1.5)
 
@@ -100,14 +100,14 @@
           send_mock_content(res, 'content')
         end
 
-        stub_request(:get, config.auth_service_url).to_return(status: 200, body: body_response)
+        stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 200, body: body_response)
         config.streaming_service_url = server.base_uri
 
         sse_handler = SplitIoClient::SSE::SSEHandler.new(config, splits_worker, segments_worker, sse_client)
         push_manager = subject.new(config, sse_handler, api_key, runtime_producer)
         connected = push_manager.start_sse
 
-        expect(a_request(:get, config.auth_service_url)).to have_been_made.times(1)
+        expect(a_request(:get, config.auth_service_url + "?s=1.1")).to have_been_made.times(1)
 
         sleep(1.5)
 
diff --git a/spec/engine/sync_manager_spec.rb b/spec/engine/sync_manager_spec.rb
index 7bedc97b..d472de01 100644
--- a/spec/engine/sync_manager_spec.rb
+++ b/spec/engine/sync_manager_spec.rb
@@ -68,7 +68,7 @@
     mock_segment_changes('segment2', segment2, '-1')
     mock_segment_changes('segment2', segment2, '1470947453878')
     mock_segment_changes('segment3', segment3, '-1')
-    stub_request(:get, config.auth_service_url).to_return(status: 200, body: body_response)
+    stub_request(:get, config.auth_service_url + "?s=1.1").to_return(status: 200, body: body_response)
     stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
   end
 
@@ -84,7 +84,7 @@
       sync_manager.start
 
       sleep(2)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
 
       expect(config.threads.size).to eq(11)
       config.threads.values.each { |thread| Thread.kill(thread) }
@@ -104,7 +104,7 @@
       sync_manager.start
 
       sleep(2)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
 
       expect(config.threads.size).to eq(8)
       config.threads.values.each { |thread| Thread.kill(thread) }
@@ -136,7 +136,7 @@
   private
 
   def mock_split_changes_with_since(splits_json, since)
-    stub_request(:get, "https://sdk.split.io/api/splitChanges?since=#{since}")
+    stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=#{since}")
       .to_return(status: 200, body: splits_json)
   end
 
diff --git a/spec/engine/synchronizer_spec.rb b/spec/engine/synchronizer_spec.rb
index 5a406419..74599346 100644
--- a/spec/engine/synchronizer_spec.rb
+++ b/spec/engine/synchronizer_spec.rb
@@ -52,7 +52,7 @@
 
       sleep(2)
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment2?since=-1')).to have_been_made.once
@@ -66,7 +66,7 @@
 
       sleep(2)
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment2?since=-1')).to have_been_made.once
@@ -84,7 +84,7 @@
     it 'start_periodic_fetch' do
       synchronizer.start_periodic_fetch
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=-1')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.once
       expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment2?since=-1')).to have_been_made.once
@@ -94,7 +94,7 @@
   end
 
   it 'sync_all synchronous - should return false' do
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 500)
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 500)
 
     result = synchronizer.sync_all(false)
 
@@ -112,11 +112,11 @@
     mock_segment_changes('segment1', segment1, '1470947453877')
 
     synchronizer.fetch_splits(0)
-    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
   end
 
   it 'fetch_splits - with CDN bypassed' do
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body:
     '{
       "splits": [],
@@ -124,7 +124,7 @@
       "till": 1506703262918
     }')
 
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918')
       .to_return(status: 200, body:
     '{
       "splits": [],
@@ -132,7 +132,7 @@
       "till": 1506703262918
     }')
 
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262920')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918&till=1506703262920')
       .to_return(status: 200, body:
     '{
       "splits": [],
@@ -142,9 +142,9 @@
 
     synchronizer.fetch_splits(1_506_703_262_920)
 
-    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
-    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')).to have_been_made.times(9)
-    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262920')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918')).to have_been_made.times(9)
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918&till=1506703262920')).to have_been_made.once
   end
 
   it 'fetch_segment' do
@@ -227,7 +227,7 @@
 private
 
 def mock_split_changes(splits_json)
-  stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 200, body: splits_json)
+  stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 200, body: splits_json)
 end
 
 def mock_segment_changes(segment_name, segment_json, since)
diff --git a/spec/engine_spec.rb b/spec/engine_spec.rb
index 1919879c..8d09ae25 100644
--- a/spec/engine_spec.rb
+++ b/spec/engine_spec.rb
@@ -46,7 +46,7 @@
       @mode = cache_adapter.equal?(:memory) ? :standalone : :consumer
       stub_request(:any, /https:\/\/telemetry.*/).to_return(status: 200, body: 'ok')
       stub_request(:any, /https:\/\/events.*/).to_return(status: 200, body: '')
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
       .to_return(status: 200, body: '')
     end
 
@@ -126,7 +126,7 @@
 
     context '#get_treatment' do
       before do
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/).to_return(status: 200, body: '')
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/).to_return(status: 200, body: '')
 
         load_splits(all_keys_matcher_json, flag_sets_json)
         subject.block_until_ready
@@ -832,7 +832,7 @@
       before do
         impressions_test_json = File.read(File.join(SplitIoClient.root, 'spec/test_data/splits/engine/impressions_test.json'))
         load_splits(impressions_test_json, flag_sets_json)
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/).to_return(status: 200, body: '')
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/).to_return(status: 200, body: '')
       end
 
       it 'returns correct impressions for get_treatments checking ' do
@@ -926,7 +926,7 @@
       end
 
       it 'returns control' do
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
           .to_return(status: 200, body: all_keys_matcher_json)
 
         subject.block_until_ready
@@ -940,7 +940,7 @@
 
     describe 'redis outage' do
       before do
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
           .to_return(status: 200, body: all_keys_matcher_json)
       end
 
@@ -953,7 +953,7 @@
 
     describe 'events' do
       before do
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
           .to_return(status: 200, body: all_keys_matcher_json)
         subject.block_until_ready
       end
@@ -983,7 +983,7 @@
 
     context '#track' do
       before do
-        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since/)
+        stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since/)
           .to_return(status: 200, body: all_keys_matcher_json)
         subject.block_until_ready
       end
@@ -1190,7 +1190,7 @@
     end
 
     before do
-      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since.*/)
+      stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since.*/)
       .to_return(status: 200, body: all_keys_matcher_json)
     end
 
@@ -1267,7 +1267,7 @@
 
 def load_splits(splits_json, flag_sets_json)
   if @mode.equal?(:standalone)
-    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?since.*/)
+    stub_request(:get, /https:\/\/sdk\.split\.io\/api\/splitChanges\?s=1\.1&since.*/)
     .to_return(status: 200, body: splits_json)
   else
     add_splits_to_repository(splits_json)
diff --git a/spec/integrations/dedupe_impression_spec.rb b/spec/integrations/dedupe_impression_spec.rb
index 8aa67ef7..399d3045 100644
--- a/spec/integrations/dedupe_impression_spec.rb
+++ b/spec/integrations/dedupe_impression_spec.rb
@@ -33,8 +33,8 @@
   context 'checking logic impressions' do
     it 'get_treament should post 7 impressions - debug mode' do
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '')
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=-1").to_return(status: 200, body: splits, headers: {})
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=-1").to_return(status: 200, body: splits, headers: {})
 
       factory = SplitIoClient::SplitFactory.new('test_api_key_debug-1', streaming_enabled: false, impressions_mode: :debug)
       debug_client = factory.client
@@ -61,7 +61,7 @@
 
     it 'get_treaments should post 9 impressions - debug mode' do
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '')
 
       factory = SplitIoClient::SplitFactory.new('test_api_key_debug-2', streaming_enabled: false, impressions_mode: :debug)
       debug_client = factory.client
@@ -81,7 +81,7 @@
 
     it 'get_treament should post 3 impressions - optimized mode' do
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/usage').to_return(status: 200, body: '')
 
       factory = SplitIoClient::SplitFactory.new('test_api_key-1', streaming_enabled: false, impressions_mode: :optimized, impressions_refresh_rate: 60)
@@ -113,7 +113,7 @@
     it 'get_treaments should post 8 impressions - optimized mode' do
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/usage').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '')
 
       factory = SplitIoClient::SplitFactory.new('test_api_key-2', streaming_enabled: false, impressions_mode: :optimized)
       client = factory.client
@@ -149,7 +149,7 @@
 private
 
 def mock_split_changes_v2(splits_json)
-  stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+  stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
     .to_return(status: 200, body: splits_json)
 end
 
diff --git a/spec/integrations/in_memory_client_spec.rb b/spec/integrations/in_memory_client_spec.rb
index 85956360..1120b57a 100644
--- a/spec/integrations/in_memory_client_spec.rb
+++ b/spec/integrations/in_memory_client_spec.rb
@@ -47,7 +47,7 @@
 
   context '#get_treatment' do
     it 'returns treatments with FACUNDO_TEST feature and check impressions' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       expect(client.get_treatment('nico_test', 'FACUNDO_TEST')).to eq 'on'
       expect(client.get_treatment('mauro_test', 'FACUNDO_TEST')).to eq 'off'
@@ -71,7 +71,7 @@
     end
 
     it 'returns treatments with Test_Save_1 feature and check impressions' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       expect(client.get_treatment('1', 'Test_Save_1')).to eq 'on'
       expect(client.get_treatment('24', 'Test_Save_1')).to eq 'off'
@@ -95,7 +95,7 @@
     end
 
     it 'returns treatments with input validations' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       expect(client.get_treatment('nico_test', 'FACUNDO_TEST')).to eq 'on'
       expect(client.get_treatment('', 'FACUNDO_TEST')).to eq 'control'
@@ -123,7 +123,7 @@
     end
 
     it 'returns CONTROL with treatment doesnt exist' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       expect(client.get_treatment('nico_test', 'random_treatment')).to eq 'control'
 
       impressions = custom_impression_listener.queue
@@ -131,7 +131,7 @@
     end
 
     it 'returns CONTROL when server return 500' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       mock_split_changes_error
 
       expect(client.get_treatment('nico_test', 'FACUNDO_TEST')).to eq 'control'
@@ -148,7 +148,7 @@
     end
 
     it 'with multiple factories returns on' do
-#      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+#      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       local_log = StringIO.new
       logger = Logger.new(local_log)
 
@@ -228,7 +228,7 @@
 
   context '#get_treatment_with_config' do
     it 'returns treatments and configs with FACUNDO_TEST treatment and check impressions' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       expect(client.get_treatment_with_config('nico_test', 'FACUNDO_TEST')).to eq(
         treatment: 'on',
@@ -258,7 +258,7 @@
     end
 
     it 'returns treatments and configs with MAURO_TEST treatment and check impressions' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
 
       expect(client.get_treatment_with_config('mauro', 'MAURO_TEST')).to eq(
@@ -289,7 +289,7 @@
     end
 
     it 'returns treatments with input validations' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
 
       expect(client.get_treatment_with_config('nico_test', 'FACUNDO_TEST')).to eq(
@@ -336,7 +336,7 @@
     end
 
     it 'returns CONTROL with treatment doesnt exist' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
 
       expect(client.get_treatment_with_config('nico_test', 'random_treatment')).to eq(
@@ -350,7 +350,7 @@
     end
 
     it 'returns CONTROL when server return 500' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       mock_split_changes_error
 
       expect(client.get_treatment_with_config('nico_test', 'FACUNDO_TEST')).to eq(
@@ -372,7 +372,7 @@
 
   context '#get_treatments' do
     before do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
     end
 
     it 'returns treatments and check impressions' do
@@ -476,7 +476,7 @@
 
   context '#get_treatments_by_flag_set' do
     before do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
     end
 
     it 'returns treatments and check impressions' do
@@ -561,7 +561,7 @@
 
   context '#get_treatments_by_flag_sets' do
     before do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
     end
 
     it 'returns treatments and check impressions' do
@@ -644,7 +644,7 @@
 
   context '#get_treatments_with_config_by_flag_set' do
     before do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
     end
 
     it 'returns treatments and check impressions' do
@@ -754,7 +754,7 @@
 
   context '#get_treatments_with_config_by_flag_sets' do
     before do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
     end
 
     it 'returns treatments and check impressions' do
@@ -858,7 +858,7 @@
 
   context '#get_treatments_with_config' do
     it 'returns treatments and check impressions' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       result = client.get_treatments_with_config('nico_test', %w[FACUNDO_TEST MAURO_TEST Test_Save_1])
       expect(result[:FACUNDO_TEST]).to eq(
@@ -898,7 +898,7 @@
     end
 
     it 'returns treatments with input validation' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       result1 = client.get_treatments_with_config('nico_test', %w[FACUNDO_TEST "" nil])
       result2 = client.get_treatments_with_config('', %w["" MAURO_TEST Test_Save_1])
@@ -937,7 +937,7 @@
     end
 
     it 'returns CONTROL with treatment doesnt exist' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       client.block_until_ready
       result = client.get_treatments_with_config('nico_test', %w[FACUNDO_TEST random_treatment])
 
@@ -962,7 +962,7 @@
     end
 
     it 'returns CONTROL when server return 500' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1506703262916").to_return(status: 200, body: 'ok')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916").to_return(status: 200, body: 'ok')
       mock_split_changes_error
 
       result = client.get_treatments_with_config('nico_test', %w[FACUNDO_TEST MAURO_TEST Test_Save_1])
@@ -1082,7 +1082,7 @@
   context '#track' do
     it 'returns true' do
       stub_request(:post, 'https://events.split.io/api/events/bulk').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '')
 
       properties = {
         property_1: 1,
@@ -1141,7 +1141,7 @@
         flag_sets_filter: ['set_3', '@3we'])
     end
       before do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?sets=set_3&since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1&sets=set_3')
       .to_return(status: 200, body: splits)
       mock_segment_changes('segment1', segment1, '-1')
       mock_segment_changes('segment1', segment1, '1470947453877')
@@ -1203,12 +1203,12 @@
 private
 
 def mock_split_changes(splits_json)
-  stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+  stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
     .to_return(status: 200, body: splits_json)
 end
 
 def mock_split_changes_error
-  stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+  stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
     .to_return(status: 500)
 end
 
diff --git a/spec/integrations/push_client_spec.rb b/spec/integrations/push_client_spec.rb
index b19be95e..8673bbd9 100644
--- a/spec/integrations/push_client_spec.rb
+++ b/spec/integrations/push_client_spec.rb
@@ -51,14 +51,14 @@
       mock_splits_request(splits2, '1585948850109')
       mock_splits_request(splits3, '1585948850110')
       mock_segment_changes('segment3', segment3, '-1')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
 
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_update_must_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -74,9 +74,9 @@
         client.block_until_ready
         sleep(2)
         expect(client.get_treatment('admin', 'push_test')).to eq('after_fetch')
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.at_least_times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850109')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.at_least_times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850109')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110')).to have_been_made.times(1)
         client.destroy
       end
     end
@@ -91,7 +91,7 @@
           send_content(res, event_split_update_must_not_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -105,9 +105,9 @@
         client.block_until_ready(1)
         sleep(1)
         expect(client.get_treatment('admin', 'push_test')).to eq('on')
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850109')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110')).to have_been_made.times(0)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850109')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110')).to have_been_made.times(0)
         client.destroy
       end
     end
@@ -123,7 +123,7 @@
           send_content(res, event_split_update_missing_change_number)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -137,9 +137,9 @@
         client.block_until_ready(1)
         sleep(1)
         expect(client.get_treatment('admin', 'push_test')).to eq('on')
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850109')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110')).to have_been_made.times(0)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850109')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110')).to have_been_made.times(0)
       end
     end
 
@@ -149,14 +149,14 @@
       mock_splits_request(splits3, '1585948850110')
       mock_segment_changes('segment3', segment3, '-1')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1585948850111").to_return(status: 200, body: '')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111").to_return(status: 200, body: '')
       stub_request(:get, "https://sdk.split.io/api/segmentChanges/bilal_segment?since=-1").to_return(status: 200, body: '')
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_iff_update_no_compression)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -185,13 +185,13 @@
       mock_splits_request(splits3, '1585948850110')
       mock_segment_changes('segment3', segment3, '-1')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_iff_update_incorrect_pcn)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -214,13 +214,13 @@
       mock_splits_request(splits3, '1585948850110')
       mock_segment_changes('segment3', segment3, '-1')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_iff_update_missing_definition)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -243,13 +243,13 @@
       mock_splits_request(splits3, '1585948850110')
       mock_segment_changes('segment3', segment3, '-1')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: '')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_iff_update_incorrect_compression)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -279,7 +279,7 @@
           send_content(res, event_split_kill_must_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -292,9 +292,9 @@
         client.block_until_ready
         sleep(2)
         expect(client.get_treatment('admin', 'push_test')).to eq('after_fetch')
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850109')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110')).to have_been_made.at_least_times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850109')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110')).to have_been_made.at_least_times(1)
         client.destroy
       end
     end
@@ -303,14 +303,14 @@
       mock_splits_request(splits, -1)
       mock_splits_request(splits2, 1_585_948_850_109)
       mock_segment_changes('segment3', segment3, '-1')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110').to_return(status: 200, body: '')
 
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_split_kill_must_not_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -324,9 +324,9 @@
         client.block_until_ready(1)
         sleep(2)
         expect(client.get_treatment('admin', 'push_test')).to eq('on')
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850109')).to have_been_made.times(1)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850110')).to have_been_made.times(0)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850109')).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850110')).to have_been_made.times(0)
         client.destroy
       end
     end
@@ -345,7 +345,7 @@
           send_content(res, event_segment_update_must_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -374,7 +374,7 @@
           send_content(res, event_segment_update_must_not_fetch)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -399,14 +399,14 @@
       mock_splits_request(splits2, 1_585_948_850_109)
       mock_splits_request(splits3, 1_585_948_850_110)
       mock_segment_changes('segment3', segment3, '-1')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
 
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_occupancy_with_publishers)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -435,7 +435,7 @@
           send_content(res, event_occupancy_without_publishers)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -466,7 +466,7 @@
           send_content(res, event_control_STREAMING_PAUSED)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -495,7 +495,7 @@
           send_content(res, event_control_STREAMING_RESUMED)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -518,14 +518,14 @@
       mock_splits_request(splits2, 1_585_948_850_109)
       mock_splits_request(splits3, 1_585_948_850_110)
       mock_segment_changes('segment3', segment3, '-1')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1585948850111').to_return(status: 200, body: '')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1585948850111').to_return(status: 200, body: '')
 
       mock_server do |server|
         server.setup_response('/') do |_, res|
           send_content(res, event_control_STREAMING_DISABLED)
         end
 
-        stub_request(:get, auth_service_url).to_return(status: 200, body: auth_body_response)
+        stub_request(:get, auth_service_url + "?s=1.1").to_return(status: 200, body: auth_body_response)
 
         streaming_service_url = server.base_uri
         factory = SplitIoClient::SplitFactory.new(
@@ -558,7 +558,7 @@ def send_content(res, content)
   end
 
   def mock_splits_request(splits_json, since)
-    stub_request(:get, "https://sdk.split.io/api/splitChanges?since=#{since}")
+    stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=#{since}")
       .to_return(status: 200, body: splits_json)
   end
 
diff --git a/spec/splitclient/split_factory_spec.rb b/spec/splitclient/split_factory_spec.rb
index 14a1b20d..5cfec28c 100644
--- a/spec/splitclient/split_factory_spec.rb
+++ b/spec/splitclient/split_factory_spec.rb
@@ -69,7 +69,7 @@
     let(:mode) { :standalone }
 
     it 'log an error stating Api Key is invalid' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
@@ -89,7 +89,7 @@
     let(:mode) { :standalone }
 
     it 'log an error stating Api Key is invalid' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
@@ -112,9 +112,9 @@
     end
 
     it 'log an error stating Api Key is invalid' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: splits_with_segments_json)
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1473863097220')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1473863097220')
         .to_return(status: 200, body: [])
       stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=-1')
         .to_return(status: 403, body: [])
@@ -140,7 +140,7 @@
     let(:mode) { :standalone }
 
     it 'log an error' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
 
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/usage')
@@ -174,7 +174,7 @@
     end
 
     it 'logs warnings stating number of factories' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
 
       described_class.new('API_KEY', options)
@@ -188,7 +188,7 @@
     end
 
     it 'decreases number of registered factories on client destroy' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
 
       expect(SplitIoClient.split_factory_registry.number_of_factories_for('API_KEY')).to eq 0
@@ -203,7 +203,7 @@
     end
 
     it 'active and redundant factories' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
 
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
@@ -239,7 +239,7 @@
         .to_return(status: 200, body: 'ok')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
@@ -260,7 +260,7 @@
         .to_return(status: 200, body: 'ok')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
@@ -281,7 +281,7 @@
         .to_return(status: 200, body: 'ok')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
@@ -302,7 +302,7 @@
         .to_return(status: 200, body: 'ok')
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: 'ok')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: [])
       stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
         .to_return(status: 200, body: '')
diff --git a/spec/splitclient/split_manager_spec.rb b/spec/splitclient/split_manager_spec.rb
index bc2d9c6f..4714a40f 100644
--- a/spec/splitclient/split_manager_spec.rb
+++ b/spec/splitclient/split_manager_spec.rb
@@ -10,7 +10,7 @@
   let(:segments) { File.read(File.expand_path(File.join(File.dirname(__FILE__), '../test_data/segments/engine_segments.json'))) }
 
   before do
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body: splits)
 
     stub_request(:get, 'https://sdk.split.io/api/segmentChanges/demo?since=-1')
@@ -25,7 +25,7 @@
     stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config')
       .to_return(status: 200, body: 'ok')
 
-    stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1473413807667")
+    stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1473413807667")
       .to_return(status: 200, body: "", headers: {})
   end
 
@@ -85,7 +85,7 @@
 
   context '#splits' do
     it 'returns empty array and logs error  when not ready' do
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=-1")
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=-1")
         .to_return(status: 200, body: "", headers: {})
 
       allow(subject).to receive(:ready?).and_return(false)
@@ -109,10 +109,10 @@
     let(:splits3) { File.read(File.expand_path(File.join(File.dirname(__FILE__), '../test_data/splits/splits3.json'))) }
 
     before do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: splits3)
 
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1473863097220")
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1473863097220")
         .to_return(status: 200, body: "", headers: {})
     end
 
@@ -137,10 +137,10 @@
     let(:splits4) { File.read(File.expand_path(File.join(File.dirname(__FILE__), '../test_data/splits/splits4.json'))) }
 
     before do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .to_return(status: 200, body: splits4)
 
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since")
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since")
         .to_return(status: 200, body: "", headers: {})
     end
 
diff --git a/spec/splitclient_rb_corner_cases_spec.rb b/spec/splitclient_rb_corner_cases_spec.rb
index bbed0468..b5d763ea 100644
--- a/spec/splitclient_rb_corner_cases_spec.rb
+++ b/spec/splitclient_rb_corner_cases_spec.rb
@@ -21,10 +21,10 @@
 
   before do
     stub_request(:post, 'https://events.split.io/api/testImpressions/bulk').to_return(status: 200, body: '')
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 200, body: splits_json)
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 200, body: splits_json)
     stub_request(:get, 'https://sdk.split.io/api/segmentChanges/demo?since=-1').to_return(status: 200, body: segment_res)
     stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=-1').to_return(status: 200, body: segment_res)
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1473413807667').to_return(status: 200, body: segment_res)
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1473413807667').to_return(status: 200, body: segment_res)
     stub_request(:post, 'https://telemetry.split.io/api/v1/metrics/config').to_return(status: 200, body: segment_res)
     stub_request(:post, 'https://events.split.io/api/testImpressions/count').to_return(status: 200, body: '')
   end
diff --git a/spec/sse/event_source/client_spec.rb b/spec/sse/event_source/client_spec.rb
index 416b66ad..3547f6a1 100644
--- a/spec/sse/event_source/client_spec.rb
+++ b/spec/sse/event_source/client_spec.rb
@@ -48,10 +48,10 @@
 
   context 'tests' do
     it 'receive split update event' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .with(headers: { 'Authorization' => 'Bearer client-spec-key' })
         .to_return(status: 200, body: '{"splits":[],"since":-1,"till":5564531221}')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=5564531221')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=5564531221')
         .with(headers: { 'Authorization' => 'Bearer client-spec-key' })
         .to_return(status: 200, body: '{"splits":[],"since":5564531221,"till":5564531221}')
 
@@ -68,7 +68,7 @@
         expect(sse_client.connected?).to eq(true)
         expect(push_status_queue.pop(true)).to eq(SplitIoClient::Constants::PUSH_CONNECTED)
         sleep 1
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(1)
 
         sse_client.close
 
@@ -79,10 +79,10 @@
     end
 
     it 'receive split kill event' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
         .with(headers: { 'Authorization' => 'Bearer client-spec-key' })
         .to_return(status: 200, body: '{"splits":[],"since":-1,"till":5564531221}')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=5564531221')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=5564531221')
         .with(headers: { 'Authorization' => 'Bearer client-spec-key' })
         .to_return(status: 200, body: '{"splits":[],"since":5564531221,"till":5564531221}')
 
@@ -99,7 +99,7 @@
         expect(sse_client.connected?).to eq(true)
         expect(push_status_queue.pop(true)).to eq(SplitIoClient::Constants::PUSH_CONNECTED)
         sleep 1
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(1)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(1)
 
         sse_client.close
 
@@ -150,7 +150,7 @@
         expect(connected).to eq(true)
         expect(sse_client.connected?).to eq(true)
         expect(push_status_queue.pop(true)).to eq(SplitIoClient::Constants::PUSH_CONNECTED)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
         expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment-test?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
 
         sse_client.close
@@ -172,7 +172,7 @@
         expect(connected).to eq(true)
         expect(sse_client.connected?).to eq(true)
         expect(push_status_queue.pop(true)).to eq(SplitIoClient::Constants::PUSH_CONNECTED)
-        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
+        expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
         expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment-test?since=-1').with(headers: { 'Authorization' => 'Bearer client-spec-key' })).to have_been_made.times(0)
 
         sse_client.close
diff --git a/spec/sse/workers/segments_worker_spec.rb b/spec/sse/workers/segments_worker_spec.rb
index 37d6e868..aad5db85 100644
--- a/spec/sse/workers/segments_worker_spec.rb
+++ b/spec/sse/workers/segments_worker_spec.rb
@@ -101,7 +101,7 @@
   private
 
   def mock_split_changes(splits_json)
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body: splits_json)
   end
 
diff --git a/spec/sse/workers/splits_worker_spec.rb b/spec/sse/workers/splits_worker_spec.rb
index 5cae7f59..b45aef73 100644
--- a/spec/sse/workers/splits_worker_spec.rb
+++ b/spec/sse/workers/splits_worker_spec.rb
@@ -51,9 +51,9 @@
     end
 
     it 'add change number - must tigger fetch - with retries' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262918}')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918').to_return(status: 200, body: '{"splits": [],"since": 1506703262918,"till": 1506703262918}')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262919').to_return(status: 200, body: '{"splits": [],"since": 1506703262919,"till": 1506703262919}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262918}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918').to_return(status: 200, body: '{"splits": [],"since": 1506703262918,"till": 1506703262918}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918&till=1506703262919').to_return(status: 200, body: '{"splits": [],"since": 1506703262919,"till": 1506703262919}')
 
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
@@ -61,39 +61,39 @@
 
       sleep 1
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')).to have_been_made.at_least_times(2)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262919')).to have_been_made.times(1)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')).to have_been_made.times(1)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918')).to have_been_made.at_least_times(2)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262918&till=1506703262919')).to have_been_made.times(1)
     end
 
     it 'must trigger fetch' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262916}')
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '{"splits": [],"since": 1506703262916,"till": 1506703262918}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262916}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '{"splits": [],"since": 1506703262916,"till": 1506703262918}')
 
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
       worker.add_to_queue(SplitIoClient::SSE::EventSource::StreamData.new("SPLIT_UPDATE", 123, JSON.parse('{"type":"SPLIT_UPDATE","changeNumber":1506703262918}'), 'test'))
       sleep 1
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916')).to have_been_made.once
     end
 
     it 'must not trigger fetch' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262916}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262916}')
 
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
       worker.add_to_queue(SplitIoClient::SSE::EventSource::StreamData.new("SPLIT_UPDATE", 123, JSON.parse('{"type":"SPLIT_UPDATE","changeNumber":1506703262916}'), 'test'))
       sleep 1
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916')).to have_been_made.times(0)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916')).to have_been_made.times(0)
     end
 
     it 'without start, must not fetch' do
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.add_to_queue(SplitIoClient::SSE::EventSource::StreamData.new("SPLIT_UPDATE", 123, JSON.parse('{"type":"SPLIT_UPDATE","changeNumber":1506703262918}'), 'test'))
 
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916')).to have_been_made.times(0)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916')).to have_been_made.times(0)
     end
   end
 
@@ -136,7 +136,7 @@
     end
 
     it 'must kill split and trigger fetch' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916').to_return(status: 200, body: '{"splits": [],"since": 1506703262916,"till": 1506703262918}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916').to_return(status: 200, body: '{"splits": [],"since": 1506703262916,"till": 1506703262918}')
 
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
@@ -148,7 +148,7 @@
       expect(split[:killed]).to be_truthy
       expect(split[:defaultTreatment]).to eq('on')
       expect(split[:changeNumber]).to eq(1_506_703_262_918)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916')).to have_been_made.once
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916')).to have_been_made.once
     end
 
     it 'must kill split and must not trigger fetch' do
@@ -163,7 +163,7 @@
       expect(split[:killed]).to be_truthy
       expect(split[:defaultTreatment]).to eq('on')
       expect(split[:changeNumber]).to eq(1_506_703_262_916)
-      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262916')).to have_been_made.times(0)
+      expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1506703262916')).to have_been_made.times(0)
     end
   end
 
@@ -195,8 +195,8 @@
       SplitIoClient::Engine::Synchronizer.new(repositories, config, params)
     end
     it 'update split with and without flagset' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1234').to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 1234}')
-      stub_request(:get, "https://sdk.split.io/api/splitChanges?since=1234&till=5564531221").to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 5564531221}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1234').to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 1234}')
+      stub_request(:get, "https://sdk.split.io/api/splitChanges?s=1.1&since=1234&till=5564531221").to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 5564531221}')
       stub_request(:get, "https://sdk.split.io/api/segmentChanges/bilal_segment?since=-1").to_return(status: 200, body: "")
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
@@ -276,7 +276,7 @@
     end
 
     it 'instant ff update split notification with segment matcher.' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1234').to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 1234}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1234').to_return(status: 200, body: '{"splits": [],"since": 1234,"till": 1234}')
       stub_request(:get, 'https://sdk.split.io/api/segmentChanges/maur-2?since=-1').to_return(status: 200, body: '{"name":"maur-2","added":["admin"],"removed":[],"since":-1,"till":-1}')
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
@@ -290,7 +290,7 @@
     end
 
     it 'should not update if definition is nil' do
-      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1234').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262918}')
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=1234').to_return(status: 200, body: '{"splits": [],"since": -1,"till": 1506703262918}')
       worker = subject.new(synchronizer, config, splits_repository, telemetry_runtime_producer, segment_fetcher)
       worker.start
 
@@ -304,7 +304,7 @@
   private
 
   def mock_split_changes(splits_json)
-    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?s=1.1&since=-1')
       .to_return(status: 200, body: splits_json)
   end