diff --git a/CMakeLists.txt b/CMakeLists.txt
index 07b813c71..9cd883d72 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,7 +17,7 @@ endif()
 
 # Define project
 project(Monitoring
-  VERSION 3.0.5
+  VERSION 3.0.6
   DESCRIPTION "O2 Monitoring library"
   LANGUAGES CXX
 )
diff --git a/examples/2-TaggedMetrics.cxx b/examples/2-TaggedMetrics.cxx
index 6d8426bce..cb6f9f729 100644
--- a/examples/2-TaggedMetrics.cxx
+++ b/examples/2-TaggedMetrics.cxx
@@ -22,6 +22,6 @@ int main()
   // 10 is the value
   // myMetric is the name of the metric
   // then add predefined tag
-  monitoring->send(Metric{10, "myMetric"}.addTag(tags::Key::Detector, tags::Value::TPC));
-  monitoring->send(Metric{10, "myMetric"}.addTag(tags::Key::CRU, 123));
+  monitoring->send(Metric{10, "myMetric"}.addTag(tags::Key::Detector, tags::Value::ACO));
+  monitoring->send(Metric{10, "myMetric"}.addTag(tags::Key::CRU, 0));
 }
diff --git a/include/Monitoring/Tags.h b/include/Monitoring/Tags.h
index aae0c4404..451206a3c 100644
--- a/include/Monitoring/Tags.h
+++ b/include/Monitoring/Tags.h
@@ -64,7 +64,7 @@ static constexpr std::array<std::string_view, 13> TAG_KEY = {
 
 // Tag values
 enum class Value : unsigned short int {
-  ACO,
+  Null,
   AD,            // 1
   CPV,           // 2
   EMC,           // 3
@@ -101,12 +101,13 @@ enum class Value : unsigned short int {
   PerCycle,      // 34
   PerRun,        // 35
   Monitoring,    // 36
-  CRORC
+  CRORC,         // 37
+  ACO            // 38
 };
 
 // Tag value array
-static constexpr std::array<std::string_view, 38> TAG_VALUE = {{
-  "ACO"sv,
+static constexpr std::array<std::string_view, 39> TAG_VALUE = {{
+  "Null"sv,
   "AD"sv,      // 1
   "CPV"sv,     // 2
   "EMC"sv,     // 3
@@ -142,13 +143,14 @@ static constexpr std::array<std::string_view, 38> TAG_VALUE = {{
   "ps"sv,      // 33
   "pcycle"sv,  // 34
   "prun"sv,    // 35
-  "monitoring"sv,
-  "CRORC"sv
+  "monitoring"sv, // 36
+  "CRORC"sv,   // 37
+  "ACO"sv      // 38
 }};
 
 static constexpr std::string_view GetValue(const int value)
 {
-  return value >= 0 ? TAG_VALUE[value] : std::to_string(0 - value);
+  return value > 0 ? TAG_VALUE[value] : std::to_string(0 - value);
 }
 
 } // namespace tags