Migrating from 2.x to 3.0

(Optional) Expanding your Pack file

You should add a SHA-256 checksum to your entries in the CSV. More Details. Furthermore you can also add flags. Thats it

Updating the MultiMC instance

(Alternative 1) Create a new MultiMC instance config [Recommended]

Follow the relevant step of the getting started guide

(Alternative 2) Update PackUpdate in-place

1. Update UpdateUpdater - You can find the latest version at its own repo
2. Update the Pre-Launch command to have exactly two parameters: client and 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

Please be aware that PackUpdate will attempt to redownload all your mods after the upgrade. You can also delete both the PackUpdate.jar created by the old UpdaterUpdater and the local state file. PackUpdate 3.x will automatically create a packupdate directory in your minecraft directory and keep any local files there.