32-bit build can require whatever, but even it runs on Sailfish OS 2.x, Jolla Store client stops showing it on 2.x and 3.x. devices if I drop in aarch64 rpm. Because the whole thing starts to “require” 4.x
My 32-bit apps actually do run on 3.x (some even 2.x) devices because they are built on top of stable C/C++ APIs and compiled against 2.x SDK. Obviously, I want my apps to be available on all supported versions of Sailfish OS.