I have a Google Cloud Platform installation of 3CX PRO, with v15.5. Everything was working great, but since i upgraded (mistakenly) to the v15.5 BETA version, i began to experience call dropping after about 2 minutes into the call. I hoped that with the release of the v15.5 RC and definitive v15.5 things would have fixed themselves, it was a beta after all. Sadly the issue persisted. Furthermore I had to downgrade the firmware of all the Yealink phones to x.81.0.60 instead of x.81.0.61, otherwise no audio could be heard in calls between extensions. Someone else has the same issues? Some idea how to fix this?