Samsung Galaxy ACE 3 (GT-S7275Y) Firmware Overview
The archive lists 3 official builds for the Samsung Galaxy ACE 3 across 1 region (CSC). The newest one is S7275YDUUAPD1, released May 23, 2016 with Android 4.2.2. It is a feature update on bootloader binary 30: once a phone runs it, firmware with a lower binary can no longer be flashed (how to read a build number).
How to Flash GT-S7275Y Firmware
Put the Samsung Galaxy ACE 3 into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Pick a build with the same or a higher Bit than the one installed — a lower bootloader binary will be rejected.