diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31638c287..ccbfd3c69 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -102,6 +102,7 @@ list(APPEND _SwiftFoundation_versions
     "6.1"
     "6.2"
     "6.3"
+    "6.4"
     )
 
 # Each availability name to define
diff --git a/Package.swift b/Package.swift
index a2b1ccf4b..5ae7737a6 100644
--- a/Package.swift
+++ b/Package.swift
@@ -9,7 +9,7 @@ import CompilerPluginSupport
 let availabilityTags: [_Availability] = [
     _Availability("FoundationPreview"), // Default FoundationPreview availability
 ]
-let versionNumbers = ["6.0.2", "6.1", "6.2", "6.3"]
+let versionNumbers = ["6.0.2", "6.1", "6.2", "6.3", "6.4"]
 
 // Availability Macro Utilities