diff --git a/post_cache_action.sh b/post_cache_action.sh
index a6a5689..e057f72 100755
--- a/post_cache_action.sh
+++ b/post_cache_action.sh
@@ -26,10 +26,14 @@ debug="${5}"
 test "${debug}" = "true" && set -x
 
 # Repositories to add before installing packages.
-add_repository="${6}"
-
-# List of the packages to use.
-packages="${@:7}"
+# Keep compatibility with older action versions that only passed 6 args.
+if [ "$#" -ge 7 ]; then
+  add_repository="${6}"
+  packages="${@:7}"
+else
+  add_repository=""
+  packages="${@:6}"
+fi
 
 if test "${cache_hit}" = "true"; then
   ${script_dir}/restore_pkgs.sh "${cache_dir}" "${cache_restore_root}" "${execute_install_scripts}" "${debug}"
diff --git a/pre_cache_action.sh b/pre_cache_action.sh
index 5cb64cb..902a4b7 100755
--- a/pre_cache_action.sh
+++ b/pre_cache_action.sh
@@ -25,10 +25,14 @@ execute_install_scripts="${3}"
 debug="${4}"
 
 # Repositories to add before installing packages.
-add_repository="${5}"
-
-# List of the packages to use.
-input_packages="${@:6}"
+# Keep compatibility with older action versions that only passed 5 args.
+if [ "$#" -ge 6 ]; then
+  add_repository="${5}"
+  input_packages="${@:6}"
+else
+  add_repository=""
+  input_packages="${@:5}"
+fi
 
 # Trim commas, excess spaces, and sort.
 log "Normalizing package list..."