Limits of Capacitor native updates for Ionic upgrades

A major Ionic upgrade may also require a matching Capacitor native migration, but the web framework and native projects do not have identical change boundaries. The documented Capacitor update capability automates native configuration migration, while custom code added directly under android/ and ios/ is not managed by the Ionic CLI.

The goal is to define which native changes can be accepted as generated output and which must be treated as project-owned code. The target Ionic and Capacitor versions are not specified, and the update behavior may vary by major release, so the answer must be bounded by the matching official migration guide rather than a general assumption that any native edit is preserved or replaced.

Which file categories can the documented update workflow modify during that migration? Is there a supported mechanism for identifying generated changes separately from custom native code? What version-control baseline is required to evaluate an unsuccessful migration and recover the native projects without discarding local modifications?