You probably need to re-add the repo as per the update guide: How to update AMP to the latest version
Either that or there is another issue with your apt repos preventing updates. Any errors when apt update is run as root?
You probably need to re-add the repo as per the update guide: How to update AMP to the latest version
Either that or there is another issue with your apt repos preventing updates. Any errors when apt update is run as root?