Sony Mobile has announced that it is adding 64-bit devices to its AOSP project, which includes the Xperia Z3+ and Xperia Z4 Tablet (both LTE/Wi-Fi versions). The addition of Sony’s latest flagships to its Open Device project means that developers can build AOSP versions for these devices. Sony has also updated the software binaries for AOSP Lollipop (Android 5.1), all details of which can be found in the source link below.
Sony confirmed that whilst the 64-bit Xperia M4 Aqua has also been added to Sony’s GitHub account, at the moment it is not possible to unlock the device. Hopefully that will change in the coming weeks.