> Migrating Spring Boot apps from 3.x t 4.x is now easy given all the tooling available.

Is this true now? I used Claude-backed Cline in March to make that migration, and it got SO much wrong, mainly due to the lack of solid documentation and example code for it, I imagine. Probably the project where I've had to fix the most AI mistakes so far (it was incapable of fixing the mistakes itself, it just kept getting it wrong in different ways).