Merge pull request #1533 from buildkite/fix/agent_scaler_version_req_SUP-4279

Author: scadu

templates/aws-stack.yml

@@ -210,8 +210,8 @@ Parameters:
   BuildkiteAgentScalerVersion:
     Description: "Version of the buildkite-agent-scaler to use."
     Type: String
-    AllowedPattern: '^(?:(?:[2-9]|[1-9]\d+)\.\d+\.\d+|1\.(?:[1-9]\d+\.\d+|9\.[1-9]\d*))$'
-    ConstraintDescription: "The agent scaler release must be greater than 1.9.0 as a new parameter was introduced in 1.9.1"
+    AllowedPattern: '^(?:(?:[2-9]|[1-9]\d+)\.\d+\.\d+|1\.(?:[1-9]\d+\.\d+|9\.(?:[5-9]|[1-9]\d+)))$'
+    ConstraintDescription: "The agent scaler release must be 1.9.5 or newer."
     Default: "1.9.5"
 
   ScalerEnableExperimentalElasticCIMode: