Check Engine

New in 0.18.0

"Invalid player data" explained
- Kicked with "Invalid player data"? Check Engine now tells you which mod broke the join and how to fix it, right on the kick screen.
- Known causes so far: old LuckPerms builds, FTB Essentials / FTB Library player data, and a broken player save file (it tells you which file to swap with its backup copy).
- If the kick screen didn't explain it, the next launch shows it on the title screen.
- Kicked from someone else's server: it tells you the reason is in the server's log and what to ask the owner.
- /checkengine join explains the last kick (singleplayer, or for server ops).

Also new
- "Fixed!" popup: when a problem from your last launch is gone, a small popup says what got fixed.
- Back up before going back a version: when a mod is older than the last time the pack worked, Check Engine offers a copy of your most recently played worlds before you open one.