I'm a bit concerned about that too. When setting it up, I found a lot of their docs on github mentioned they have `template` and `expand-env` "configuration filters", then it took me entirely too long to realize that while the 4.38 pre-release notes, posted in January 2023, say it's "just around the corner", it's still being worked on.
Having said that, there still seems to be somewhat active development. It may just be one person at this point.
https://hub.docker.com/layers/authelia/authelia/v4.38.0-beta...
Our official docs can be found at https://www.authelia.com and you can find docs for a particular PR in the relevant PR. We've also linked the pre-release docs in the pre-release discussions which can be found here: https://github.com/authelia/authelia/discussions/categories/...
I can understand the security concerns but we are regularly taking measures to ensure no zero-day vulnerabilities exist, there are no known vulnerabilities with Authelia at the present time either directly or via the code-paths of dependencies we actually use.
The updates to the AUR package were not about new releases since 2022:
aur/authelia $ git log ad4e6ca^..HEAD
2c5029d (2023-10-09) Amir Zarrinkafsh ECDB8EF9E77E4EBF (HEAD -> authelia, origin/authelia) Fix frozek lockfile issue with pnpm
246d77c (2023-01-22) Amir Zarrinkafsh ECDB8EF9E77E4EBF Utilise pnpm instead of yarn
ad4e6ca (2022-12-21) Amir Zarrinkafsh Update to v4.37.5