Share your experience!
Today build 34.4.A.2.97 came available (The Netherlands), containing the Androïd security updates from july. I installed the update through Xperia Companion. So far no problems. Merely the clock layout on the lock screen had changed after the update, which I had to set to the preferred layout again.
I had the same wifi problem with an XZ1 Compact, but never with an X Compact. Perhaps Sony has had quality control issues with their component source.