diff --git a/build_tools/services.rb b/build_tools/services.rb
index 6445e775392..80de0cdc460 100644
--- a/build_tools/services.rb
+++ b/build_tools/services.rb
@@ -12,7 +12,7 @@ class ServiceEnumerator
     MINIMUM_CORE_VERSION = "3.254.0"
 
     # Minimum `aws-sdk-core` version for new S3 gem builds
-    MINIMUM_CORE_VERSION_S3 = "3.254.0"
+    MINIMUM_CORE_VERSION_S3 = "3.254.1"
 
     EVENTSTREAM_PLUGIN = "Aws::Plugins::EventStreamConfiguration"
 
diff --git a/gems/aws-sdk-core/CHANGELOG.md b/gems/aws-sdk-core/CHANGELOG.md
index 30cc67558d2..ff14a7e6e0a 100644
--- a/gems/aws-sdk-core/CHANGELOG.md
+++ b/gems/aws-sdk-core/CHANGELOG.md
@@ -1,5 +1,6 @@
 Unreleased Changes
 ------------------
+* Issue - Fix a double space appearing in the frameworks section of the User-Agent header.
 
 3.254.0 (2026-07-09)
 ------------------
diff --git a/gems/aws-sdk-core/lib/aws-sdk-core/plugins/user_agent.rb b/gems/aws-sdk-core/lib/aws-sdk-core/plugins/user_agent.rb
index 7bd7546338f..9134d33b69b 100644
--- a/gems/aws-sdk-core/lib/aws-sdk-core/plugins/user_agent.rb
+++ b/gems/aws-sdk-core/lib/aws-sdk-core/plugins/user_agent.rb
@@ -211,7 +211,7 @@ def framework_metadata
 
               frameworks[match[:name]] = match[:version]
             end
-            frameworks.map { |n, v| "lib/#{n}##{v}" }.join(' ')
+            frameworks.map { |n, v| "lib/#{n}##{v}" }.join(' ') unless frameworks.empty?
           end
 
           def metric_metadata