Sony has published a list of devices that will get an update to Android 5.1 Lollipop. Users of phones and tablets that got the official Android 5.0 already should not be worried as Lollipop will be bumped on those devices in July. The list contains no less than twenty devices that should get the OTA notification before this fall. Below is the list of supported models:

Xperia Z4
Xperia Z4 Tablet
Xperia Z3+
Xperia Z3+ Dual
Xperia Z3 (Z3 Dual)
Xperia Z3 Compact
Xperia Z3 Compact Tablet
Xperia Z2
Xperia Z2 Tablet
Xperia Z1
Xperia Z1 Compact
Xperia Z Ultra
Xperia Z
Xperia ZL
Xperia ZR
Xperia Tablet Z
Xperia T2 Ultra (T2 Ultra Dual)
Xperia C3 (Xperia C3 Dual)
Xperia M2
Xperia M2 Dual
Xperia M2 Aqua
Xperia M4 Aqua, Xperia E4 and Xperia C4 are believed to get the Android 5.1 Lollipop too, but this should take place in August. The bad news is that phones like Xperia T3 and Xperia E3 will likely remain at Android 4.4 KitKat. There is no confirmation about update availability either at the Sony Blog or official product pages. Luckily enough there are some custom ROMs that can easily become daily drivers even without Sony’s blessing. Just unlock your phone's bootloader and flash a custom rom ( cyanogenmod preferably )