Will an Android 4.3 upgrade rewrite my custom /etc/gps.conf file? Will an Android 4.3 upgrade rewrite my custom /etc/gps.conf file?
In my case, the upgrade to the android 4.3 did not replaced my custom /etc/gps.conf file.

It was edited by hands on rooted device before the Android upgrade and stayed with the same content afterwards.

Answering myself :)