diff --git a/bundler.js b/bundler.js
index adc9673..c9556f6 100644
--- a/bundler.js
+++ b/bundler.js
@@ -202,7 +202,7 @@ export async function bundleInstall(gemfile, lockFile, platform, engine, rubyVer
 
 async function computeBaseKey(platform, engine, version, lockFile, cacheVersion) {
   const cacheVersionSuffix = DEFAULT_CACHE_VERSION === cacheVersion ? '' : `-cachever:${cacheVersion}`
-  let key = `setup-ruby-bundler-cache-v3-${platform}-${engine}-${version}${cacheVersionSuffix}`
+  let key = `setup-ruby-bundler-cache-v4-${platform}-${engine}-${version}${cacheVersionSuffix}`
 
   if (common.isHeadVersion(version)) {
     if (engine !== 'jruby') {
diff --git a/dist/index.js b/dist/index.js
index a2b9860..b599e9b 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -216,7 +216,7 @@ async function bundleInstall(gemfile, lockFile, platform, engine, rubyVersion, b
 
 async function computeBaseKey(platform, engine, version, lockFile, cacheVersion) {
   const cacheVersionSuffix = DEFAULT_CACHE_VERSION === cacheVersion ? '' : `-cachever:${cacheVersion}`
-  let key = `setup-ruby-bundler-cache-v3-${platform}-${engine}-${version}${cacheVersionSuffix}`
+  let key = `setup-ruby-bundler-cache-v4-${platform}-${engine}-${version}${cacheVersionSuffix}`
 
   if (common.isHeadVersion(version)) {
     if (engine !== 'jruby') {