My cousins are both on S3's that originally had 4.0 or 4.1 I guess it was. Anyhow, they're running custom recoveries, so they don't have to worry about locked bootloaders or anything.
When their contracts end in September, they'll be upgrading their phones (probably to the new F5/prime S5). And I'll help them list the old phones.
I'll need them to go back to stock of course. But I don't want to flash a stock that removes custom-recovery capabilities. What is the most recent firmware version that would be okay to go back to? I have an account at sammobile so I can download firmwares.