The Android version of UltimaDark is available primarily to satisfy a few users, but it is not actively tested. However, since it is identical to the browser version, it inherits bug fixes and new features automatically. While we’re happy to hear that some users have it working, please remember that UltimaDark remains a highly niche and experimental project, so your experience may vary.
That said, detection of the system night mode on desktop is already planned. If Android Firefox shares dark theme information with web extensions as Firefox Desktop does—which is very probably the case—then the Android version should inherit this functionality once implemented, with a bit of luck.
