Hey,
I've wanted to migrate my package from 1.10 to 1.11 when I noticed that I can not read Flux models with BSON anymore. It does not matter whether these are old models (saved in 1.10) or new ones. I can give a MWE if needed but I think this should happen with any struct.
I tried to figure out a fix but I don't know how the new Memory type introduced in 1.11 "knows" where it fields are such that one can assign the correct values when loading with BSON.
I hope you can figure out a solution. In the meantime I will try to migrate to JLD2.
Best,
Heiner