I downloaded and installed 2.3.9 this morning (both Windows and Maestro versions.) .The install went very cleanly. However, after about 20 minutes, while transmitting, the 6500 started 'Clicking' and the audio started to drift. I had this problem a while back and had to send the 6500 back for phase-lock loop repair. Not wanting to do that again, I downgraded to v2.3.7 and the 6500 has been running now for well over an hour with no issues. This is the first time that I've had to do this to keep the radio running. Before I downgraded, I did the clearing and rebooting and full power off and it still did the clicking and drifting. So I guess for the moment, I stuck with v2.3.7. I wonder if anybody else has experienced something similar?