To add onto this, if you care about supply chain attacks, bitwarden mobile supports Fdroid builds (albeit not part of the main repo because they rely on xamarin) so you can host your own fdroid repo and run your own builds if so desired.
I think they meant if they don't like the direction that the Android client takes, i.e. they stop allowing you to change the backend url for example in which case, yes you would need to fork or rewrite it
It's fragile if you do that. Bitwarden updated their API last month on the clients so you couldn't connect to Vaultwarden at all until the Vaultwarden team could reverse engineer the change and produce a new release.
In my case I could continue to use the app, it broke the ability to sign into the vault. If you only lock your vault and not fully logout you may not have noticed it.
Thanks. I do not even lock BW, not to mention logging out, and almost never connect to the vault via the web interface - so yes I must have simply missed it.
Sorry probably not the best wording. If Bitwarden changes their API the Vaultwarden team has to act fast enough to get the same changes into the Rust version before Bitwarden updates the clients. In one case they weren't fast enough https://github.com/dani-garcia/vaultwarden/issues/3082