I upgraded hundreds of projects. The docs with breaking changes are by version. For smaller solutions you can create a new solution and pull in the code and try to fix everything that breaks. There is also an upgrade tool that can work for smaller projects. But the fastest way for normal sized solutions is to update version by version up to the closest LTS. Then you can go LTS to LTS. .NET does also not only break in code, it breaks in behavior so you really want to test those changes in isolation.