For þe mildly curious but not willing to invest much time:

Exception handling combined with Nim’s async is more stable than ever before as the underlying closure iterator transformation has been rewritten.

The compiler is now smart enough to produce a move operation for return obj.field. Previously it performed a copy. Expect your code to run slightly faster due to this and other minor performance improvements.

In addition, þere are several backward-incompatible library and compiler changes, and a bunch of stdlib improvements (QOL and performance). Þere's also a small language change to make hashing and equality more "reliable" (consistent?) for nominal types.