diff --git a/app/models/spree_avatax_official/spree/order_decorator.rb b/app/models/spree_avatax_official/spree/order_decorator.rb
index 0c15947d..d0afd971 100644
--- a/app/models/spree_avatax_official/spree/order_decorator.rb
+++ b/app/models/spree_avatax_official/spree/order_decorator.rb
@@ -88,4 +88,6 @@ def void_in_avatax
   end
 end
 
-::Spree::Order.prepend ::SpreeAvataxOfficial::Spree::OrderDecorator
+unless ::Spree::Order.ancestors.include?(::SpreeAvataxOfficial::Spree::OrderDecorator)
+  ::Spree::Order.prepend(::SpreeAvataxOfficial::Spree::OrderDecorator)
+end
diff --git a/app/models/spree_avatax_official/spree/return_authorization_decorator.rb b/app/models/spree_avatax_official/spree/return_authorization_decorator.rb
index 8e3abbb7..b913ba22 100644
--- a/app/models/spree_avatax_official/spree/return_authorization_decorator.rb
+++ b/app/models/spree_avatax_official/spree/return_authorization_decorator.rb
@@ -20,4 +20,6 @@ def refund_in_avatax
   end
 end
 
-::Spree::ReturnAuthorization.prepend(::SpreeAvataxOfficial::Spree::ReturnAuthorizationDecorator) unless 'Spree::Refund'.safe_constantize
+unless ::Spree::ReturnAuthorization.ancestors.include?(::SpreeAvataxOfficial::Spree::ReturnAuthorizationDecorator)
+  ::Spree::ReturnAuthorization.prepend(::SpreeAvataxOfficial::Spree::ReturnAuthorizationDecorator) unless 'Spree::Refund'.safe_constantize
+end
diff --git a/spree_avatax_official.gemspec b/spree_avatax_official.gemspec
index 10aa1aff..0786249b 100644
--- a/spree_avatax_official.gemspec
+++ b/spree_avatax_official.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |s| # rubocop:disable Metrics/BlockLength
   s.require_path = 'lib'
   s.requirements << 'none'
 
-  s.add_dependency 'avatax', '~> 19.3'
+  s.add_dependency 'avatax', '>= 19.3'
 
   spree_version = '>= 2.1.0'