One great thing about the development community is that they continue to support less popular devices and even some obscure devices. While the Xperia lineup is actually pretty popular the 6" T2 Ultra Dual is kinda obscure. However it is pretty developer friendly and has plenty of support from the development community. It now has an unofficial port of CyanogenMod 12 bringing Android 5.0.2 to the device. This build is a work in progress, but it already has working boot, wifi, bluetooth, audio, sdcard, video playback, fm radio, and more. Some things that aren't working include RIL, and camera. This should still be worth a try. Head to the link below to grab this rom.
via XDA