As we know their is no update for galaxy core plus from samsung,we can customize it by using custom rom. Thanks to santeri3700 xda member for providing Stable release of CyanogenMod 11 Rom based on Android Kitkat 4.4.4.Note that this is unofficial Rom.Some minor bugs are present in Rom.

Don’t miss : Download LineageOs 13 Rom for Galaxy Core Plus Android Marshmallow 6.0.1

IMPORTANT before Installing Rom

1.This Rom is Only for Samsung Galaxy Core Plus SM-G350  model.

2.You should have custom recovery installed on your device. (TWRP Recovery recommend))

Download Stable TWRP Recovery from Here and follow this guide- How to Install Custom Recovery by using odin

3. Make Backup of your current rom before flashing this Rom via Custom Recovery.

CyanogenMod 11 galaxy core plus

How to install Cyanogenmod 11 Rom on Galaxy Core Plus-

• Step By Step Guide

  1. Download Rom and Gapps from below.
  2. Place both files in external memory. 
  3. Boot into recovery mode.
  4. Now clear Cache and data.
  5. Install Cyanogenmod 11 Rom, GAPPS zip.
  6. After flashing this files Reboot device.

Downloads

Cm11 Rom- HERE
Android Kitkat Gapps- HERE

Source- xda