Lotus dev networks/git branches still active?

Going by https://github.com/filecoin-project/lotus, last commit to branch master was 2 days ago, commit 858994a.

In contrast, the other networks/branches seems to not be updated at all anymore. If they are supposedly the developer branches, shouldn’t they be ahead of the main network branch, instead of behind?

  • ntwk-nerpa last commit Nov 3, 2020, commit 3908701
  • ntwk-calibration last commit 23 days ago, commit 9b47058
  • ntwk-butterfly last commit Oct 22, 2020, commit 0c81ea6

On top of that, all the tips of the CI builds are failing.

Is Lotus not the recommended implementation to use anymore? The documentation still points to Lotus and talks about Lotus like it is the recommended way forward, but the current status of things don’t inspire a lot of confidence.