Old professional Game Maker license is now invalid? : r/gamemaker
an old GameMaker 8.1 project into the newer version of the software? license key for game maker 81 pro link
You can download the official free version from: Old professional Game Maker license is now invalid
Because the software is deprecated, the community often discusses alternative ways to keep old projects alive: Is GameMaker 8.1 Standard no longer supported? license key for game maker 81 pro link