Rails 6 → 7 Upgrade

Bigger hop than 7→8. Webpacker is gone. Zeitwerk autoloader is mandatory. Hotwire arrives. Treat it as a multi-week project for a non-trivial app.

The opinion

Dual-boot with next_rails. Hop 6.0 → 6.1 → 7.0 → 7.1. Migrate off Webpacker as a separate project before or after — never inline with the version bump. Choose importmap-rails (default) or jsbundling-rails based on app size. Adopt Hotwire (Turbo+Stimulus) gradually if you have a heavy jQuery legacy.

The hop sequence

6.0 → 6.1 → 7.0 → 7.1

Core patterns

Pattern 1: 6.0 → 6.1