Doesn't make a whole lot of sense to go with the latest android on older hardware like the S2, just the latest android that's supported by pretty much all apps now. That would be android 7 or so, the S2 would be much faster using that. An S5 could go with 7 and be that much faster as to be not noticeable to normal users. Just keep going with matching legacy phones with newer versions of android which they never got. Kinda proves a point about the whole forced sales for new OS regardless of the other toys like 50MP cameras, privacy invasion devices like fingerprint/facial recognition and other gimmiky junk for children(and clickbait ad revenue). Oh and these older phones still have replaceable batteries, headphone jacks, tool less access, microsd, sane bezels and sizes, cameras just fine for average users, sturdy materials etc you know the things that are useful.