Migrating from 2.x to 3.0

1. Update UpdateUpdater - You can find the latest version under releases
2. Update the Pre-Launch command to only have a single parameter, the Pack URL
3. (Optional) Add checksums (sha256) and flags as additional parameters to your CSV
4. Run UpdateUpdater through MultiMC and verify everything is working
5. (Optional) Set beta=true in your $INSTANCE_DIR/packupdate/updater.properties if you want to also download beta releases