Joined: 02 Aug 2012
As far as I can see, the Android build targets the ARM v5 instruction set. I am not an expert, but I think this will run on later ARM chips, but at a performance hit. The Android v7a builds for the v7a instruction set and thus will not run on earlier chips, but improves performance. See:
P.S. This is usually the case as the "unversioned" variant is the older one. You then have to add the version number when you add a newer one.