My game Does not run on older android versions.

Hi. im new to unity. and its been a 2 weeks i think i updated to unity 4.6.1 and i built my game as apk. same game which used to run on my own mobile with icecream sandwich when i had unity 4.5 is not running anymore on older android verions. i have set minimum api level to 2.3.1. someone please help me regarding this. though the game works fine on newer versions like jellybean and all.

Unity 4.6.1 had some problems running in older Android versions like 2.3.1. The problems were gradually fixed in 4.6.1 patch releases:

However, since Unity 4.6.2 is now available, it would be best to install that version instead of the latest 4.6.1 patch release.