Hi @few_meaning !
Charlie here from the App Bridge team. We have a migration guide for upgrading from v2 to v3 on the Shopify Dev Docs here. It should be quite low effort, just a couple breaking changes to the useToast and useContextualSaveBar hooks!
All major version bumps will have a migration guide posted to the same place. As for ongoing release notes, they can currently be seen via the package CHANGELOG.md’s. Stay tuned for improved release notes for all App Bridge packages!
Hope that helps!