While development for this device has aged, several stable community-built ROMs remain available on forums like XDA Developers CyanogenMod 11 (Android 4.4 KitKat):
Samsung Galaxy Pocket Neo (S5310/S5312) is a legacy device released with Android 4.1.2 Jelly Bean. Because of its hardware limitations—specifically its 850 MHz single-core processor and 512MB of RAM—installing a custom ROM can help remove background bloatware and optimize RAM usage to improve performance. Popular Custom ROMs for S5310/S5312 samsung galaxy pocket neo custom rom
This yields a usable phone for basic tasks (calls, SMS, light music, offline GPS) – much more reliable than any custom ROM. While development for this device has aged, several