diff --git a/ci/build/build-release.sh b/ci/build/build-release.sh
index 07a879c28..e484b2518 100755
--- a/ci/build/build-release.sh
+++ b/ci/build/build-release.sh
@@ -146,7 +146,7 @@ EOF
   # Include global extension dependencies as well.
   rsync "$VSCODE_SRC_PATH/extensions/package.json" "$VSCODE_OUT_PATH/extensions/package.json"
   rsync "$VSCODE_SRC_PATH/extensions/yarn.lock" "$VSCODE_OUT_PATH/extensions/yarn.lock"
-  rsync "$VSCODE_SRC_PATH/extensions/postinstall.js" "$VSCODE_OUT_PATH/extensions/postinstall.js"
+  rsync "$VSCODE_SRC_PATH/extensions/postinstall.mjs" "$VSCODE_OUT_PATH/extensions/postinstall.mjs"
 
   pushd "$VSCODE_OUT_PATH"
   symlink_asar