I upgraded my z1 from 4.2.2 (I was on this release because of Bluetooth issues with my car handsfree audio system running 4.3 as in it did not work!)
The good news is that it will now connect and allow me to use the handsfree in my car but will not display/upload the contacts. It does pop-up with a message asking me to confirm that I want to allow access to the call lists and contacts but the contacts are empty when I select them from the car audio system. The call lists display with no problems. I just wondered if there was an issue with my contacts and how they are stored on the phone... (they are synced with my google account)
I have not had any other issues with the 4.4 upgrade at all!
Any help will be appreciated!