The Samsung Galaxy S II and Galaxy Note 3, where were released 9 and 7 years ago respectively, have received an unofficial Android 10 update thanks to LineageOS developers.
The Galaxy S II was released in 2011 and its last official update, Android 4.1.2 Jelly Bean, was released in 2013.
The Galaxy Note 3 was launched in 2013 and received its last official update, Android 5.0 Lollipop, in 2015.
After this, Samsung dropped official support for these devices and did not provide any further software updates to them.
Now developers have built Android 10-based LineageOS 17.1 custom ROMs for both the ancient devices, according to XDA Developers.
The Android 10-based LineageOS 17.1 hasn't been officially announced yet, but unofficial builds are available for a variety of devices.
It's worth noting that the Radio Interface Layer (RIL) is unstable in the Galaxy S II's Android 10 port, meaning users cannot make phone calls or use mobile data which essentially prevents them from using this build for daily use.
The Galaxy Note 3's Android 10 build does not suffer from any such issues.
You can download the LineageOS 17.1 for the Galaxy S II from here and for the Galaxy Note 3 from here.