Update from 2.0.0 to 2.3.1 in Fody, causes VS2015 to not build the assembly with debug information, meaning it's impossible to put a break point. If I revert back to 2.0.0, it builds with debug info and break points come back. The same Debug build configuration is used. I also NuGet PropertyChanged.Fody but this problem occurs if I update Fody. I used PropertyChanged.Fody 2.2.0 for both cases.
try updating to version 2.3.2 https://www.nuget.org/packages/Fody/2.3.2
and in the future it is better to raise issues here https://github.com/Fody/Fody/issues