The latest Android 4.1.2 with the firmware version S5310DXAMG2 is now available for Galaxy Pocket Neo. This update is now available for Singapore Galaxy Pocket Neo GT-S5310 users. You can go to setting to check either this latest firmware is available update on your region. If available, then you can direct update on your phone or use Samsung kiesapplication.
But if your phone was rooted or running custom ROM, then you need to manuallydownload the firmware and flash into your Galaxy Pocket Neo. But , please take note that flash or modified Galaxy Pocket Neo firmware will void the phone warranty.So, Try it on your own risk.
Download S5310DXAMG2 Firmware for Galaxy Pocket Neo (Singapore): link