What Versions of Android can be used Sucessfully on Galaxy S Relay. Presently have Android 4.1.2

[AC Question]

Have Rooted My Galaxy S Relay. What is Highest & Safest Android Version that can be Used. Presently 4.1.2

 

[belodion]

Have you checked XDA Forums for custom ROMs? There is usually a description of how well they work.