Sony Mobile has released the Android 5.0.2 Lollipop firmware update for the T-Mobile Xperia Z1s (C6916). The update will move the build number from 14.4.B.0.56 to version 14.5.B.0.236. You should be able to download the update right now, but if you want to do it manually we have attached the FTF firmware file below. If you have upgraded, please post your impressions in the comments.
Thanks Darcy and Xyor!