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 develop now has a flag --unpack to run unpackPhase.

• 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 repl now has a :log command.