Perhaps off-topic but how have people upgraded TF codebases to new versions? Just last year we had a big effort to upgrade a huge code-base from 0.11 to 0.12. I feel like it should be a lot smoother than a full-team full-sprint effort.
Someone not in our team upgraded version by mistake from 0.12 to 0.13 (he was contributing something small and used the latest), the CTO got involved and made us update everything and it was a big undertaking.
Personally I have a nix shell file pinned to the exact version of terraform (as in, commit hash on the nix-packages repo) we use in every repo and just switch to that shell before doing anything.
I'm a fan of tfenv for this; it's really easy to use and makes it trivial to pin each stack to an exact version of TF.
Between rbenv, tfenv, pyenv, sdkman and so on and so forth, maybe it's time for some sort of common OS-level env-management interface...?