To ensure the add-on works correctly on Minecraft 1.21, specific steps are usually required:
If your file downloads as a .zip or a generic string of text, you must manually rename the file using a mobile file organizer such as (on Android) or the built-in Files app (on iOS). Ensure you replace .zip with .mcaddon or .mcpack so that Minecraft can open and auto-import the file with a single click. Step-by-Step Installation for MCPE 1.21 file name serppokedrockaddonmcpebase121 top