the 1.2.0 version of TLA was released for 1.21 thoug due to the minimal changes that where made in 1.21.1 it's functionality was not affected by that update and can be marked as compatible with 1.21.1 on modrinth

https://modrinth.com/mod/tla-api/version/1.2.0+mc.1.21

Thanks for testing. As the jar already has a compatible dependency, I've simply updated the modrinth listing.