diff --git a/.github/workflows/ios.yml b/.github/workflows/ios.yml
index a7f2f10..537c227 100644
--- a/.github/workflows/ios.yml
+++ b/.github/workflows/ios.yml
@@ -28,8 +28,8 @@ jobs:
             -DCMAKE_OSX_DEPLOYMENT_TARGET=9 \
             -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
             "-DMACOSX_BUNDLE_GUI_IDENTIFIER=GSL.\$(EXECUTABLE_NAME)" \
-            -DMACOSX_BUNDLE_BUNDLE_VERSION=3.1.0 \
-            -DMACOSX_BUNDLE_SHORT_VERSION_STRING=3.1.0 \
+            -DMACOSX_BUNDLE_BUNDLE_VERSION=4.2.1 \
+            -DMACOSX_BUNDLE_SHORT_VERSION_STRING=4.2.1 \
             ..
 
       - name: Build
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b306dc1..7c60893 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.14...3.16)
 
-project(GSL VERSION 4.2.0 LANGUAGES CXX)
+project(GSL VERSION 4.2.1 LANGUAGES CXX)
 
 add_library(GSL INTERFACE)
 add_library(Microsoft.GSL::GSL ALIAS GSL)
diff --git a/README.md b/README.md
index d6b251c..473b3b0 100644
--- a/README.md
+++ b/README.md
@@ -202,7 +202,7 @@ include(FetchContent)
 
 FetchContent_Declare(GSL
     GIT_REPOSITORY "https://github.com/microsoft/GSL"
-    GIT_TAG "v4.2.0"
+    GIT_TAG "v4.2.1"
     GIT_SHALLOW ON
 )