This is Itel 1507 stock firmware .pac file which is flashable via Research Download / Upgrade tool. The firmware package is made available in two different download locations for ease of access and download.
Download 1507 stock firmware package from either of the links below and follow the guide at the end of this post to learn how to flash the firmware and download tools required for flashing it.
How to flash Itel 1507 firmware
To flash Itel 1507 stock .pac rom / firmware package on your 1507 phone, follow the guide provided here