Release 2.5 (2021-12-13)
- 
The garbage collector no longer blocks new builds, so the message
waiting for the big garbage collector lock...is a thing of the past. - 
Binary cache stores now have a setting
compression-level. - 
nix developnow has a flag--unpackto rununpackPhase. - 
Lists can now be compared lexicographically using the
<operator. - 
New built-in function:
builtins.groupBy, with the same functionality as Nixpkgs'lib.groupBy, but faster. - 
nix replnow has a:logcommand.