CONFIRMED WORKING ON MY TAB 4 SM-T231 (GSM+WIFI)
1. put the device into download mode by holding power+vol down+home and connect to computer with usb cable.
2. now run odin 1.85 and select PDA and then select the openrecovery-twrp-22.214.171.124-degas.tar file
3 .hit start in odin and as soon as odin is finished the device turns off for reboot
4. press power+vol up+home to boot into twrp recovery
5. now pres reboot > system and then slide to install root
6. when device has rebooted open superuser installer app and follow instructions to update then install su binary updates then reboot.
7.Yes Now your Tab is Rooted.