The Android 5.1.1 Lollipop firmware update has now started to seed for the Sony Xperia Z3. At the time of writing, Android 5.1.1 build number 23.4.A.0.546 has been released to select regions for the D6603 variant and D6653 variant. We will include FTF firmware links to each variant below as they become live. If you have upgraded, please let us know your impressions below.
Sony Xperia Z3 FTF firmware files – Android 5.1.1 Lollipop (23.4.A.0.546)
Thanks Adrian, cachanilla86 and Jenge!