diff --git a/include/swift/AST/RuntimeVersions.def b/include/swift/AST/RuntimeVersions.def
index d04192382f47a..06c9255a7fff0 100644
--- a/include/swift/AST/RuntimeVersions.def
+++ b/include/swift/AST/RuntimeVersions.def
@@ -163,6 +163,11 @@ RUNTIME_VERSION(
   FUTURE
 )
 
+RUNTIME_VERSION(
+  (6, 3),
+  FUTURE
+)
+
 END_MAJOR_VERSION(6)
 
 // .......................................................................... //
diff --git a/stdlib/public/core/Availability.swift b/stdlib/public/core/Availability.swift
index 0ed46931dd2ca..08880a2ee57d5 100644
--- a/stdlib/public/core/Availability.swift
+++ b/stdlib/public/core/Availability.swift
@@ -240,9 +240,11 @@ extension _SwiftStdlibVersion {
   public static var v6_1_0: Self { Self(_value: 0x060100) }
   @_alwaysEmitIntoClient
   public static var v6_2_0: Self { Self(_value: 0x060200) }
+  @_alwaysEmitIntoClient
+  public static var v6_3_0: Self { Self(_value: 0x060300) }
 
   @available(SwiftStdlib 5.7, *)
-  public static var current: Self { .v6_2_0 }
+  public static var current: Self { .v6_3_0 }
 }
 
 @available(SwiftStdlib 5.7, *)
diff --git a/utils/availability-macros.def b/utils/availability-macros.def
index f816acd10afec..688055b612aa0 100644
--- a/utils/availability-macros.def
+++ b/utils/availability-macros.def
@@ -38,6 +38,7 @@ SwiftStdlib 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1
 SwiftStdlib 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0
 SwiftStdlib 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4
 SwiftStdlib 6.2:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999
+SwiftStdlib 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999
 
 # Like SwiftStdlib 5.0, but also the oldest visionOS from SwiftStdlib 5.10.
 SwiftCompatibilitySpan 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.1