How to down Android software version i.e. from Kitkat to JellyBean Plus
Usually you can't downgrade your device the "official" way, however you can do it manually:

THIS WILL VOID YOUR WARRANTY!


Go to www.sammobile.com
Then go to firmwares.
Search the right firmware for your device.
Download Odin (do a google search)
Extract Odin.zip
Put the md5/tar in the PA/PDA slot
Click on start/begin/OK.
Wait a few minutes and your will reboot.