Changes between lean 3 and lean 4

Stream: new members

[Joel McCracken]

Is there a good paper or some other information source which discusses the changes between lean 3 and 4, and especially the rational for the changes? Since we're in the middle of the transition, I think understanding this would help me quite a bit.

[Moritz Doll]

I think this is the closest thing, but there a more changes: https://leanprover.github.io/lean4/doc/lean3changes.html

[Joel McCracken]

Thank you!!