Some time ago, a severe security problem was discovered in Bluetooth devices, which had been given the name “Blueborne” by their discoverers. Operating systems like Linux and Windows already got security updates. Android is theoretically also fixed already – however, only by Google and the devices sold under their name. For devices from other manufacturers the situation is worse if the device has been on the market for more than 2 years.
At the moment I also use a Sony Xperia Z3 Compact – and there are no updates available. As a response to my support request Sony told me that a patch for “Blueborne” is only offered for the following models:
Xperia™ X Performance
Xperia™ X Compact
Xperia™ XZ Premium
Xperia™ XZ1 Compact
Xperia™ Z5 Compact
Xperia™ Z5 Premium
Xperia™ XA1 Ultra
Xperia™ XA1 Plus
The Xperia Z3 Compact was launched in September 2014 and is about 3 years old now. However, it is still sold as a new product and my copy is just over two years old.
So I will probably have to install a custom ROM again, if I want to continue to use the device together with my Smartwatch or a Bluetooth headset. But for most other users this is of course no solution and in fact they would have to buy a new device – unbelievable!
Meanwhile I use an unofficial version of LineageOS 14.1, which works fine. Also see my other other post (sorry, only in German yet, but it contains links to all the information you need in English as well).