Login toboggan is 'ported', but apparently never tested. hook_user_update has exactly one parameter in backdrop cms, but function logintoboggan_user_update uses three. I fixed it leaving only one, and submitted an issue in ghithub.

Comments

Thanks for doing that. That maintainer might no longer be involved. I can look into adding your fix and look for a new maintainer.

If I recall, Login Toboggan also has some features that can be removed from the module since they are now included in Backdrop core (such as ability to login with email address, maybe others).