The runtime may work, it may not. I really don't think it will because the 1015 runtime wouldn't even work on earlier 10.2.1 OSes. I have not tried that far back, so i doubt it would.
HOWEVER, even if it worked, you would NOT be able to install apk files, because that is a new component in the 10.2.1 OS, and it's called "app installer" process in 10.2.1.2141 or installerui in 10.2.1.1015/1259/1925 OSes. I have managed to extract this component, BUT, it will not load on pre-10.2.1.1015 OSes because it requires access to certain parts of memory that is allowed in 10.2.1.1xxx+ OSes, and not before. It will give you a memory error if you load it (yes, I've tried on multiple OSes).
So, long story short, if you want to use the apk installer, you will have to update to 10.2.1.1015+ OS. I recommend backing up and then using an autoloader just because OTA updating, or using delta update bars to jump 2 major revisions will almost definitely mess things up. Hell, even going from 10.2.0 to 10.2.1 messed things up for people in android runtime, SMS, etc
02-15-14 08:35 PM