Firmware for UCM6202/6204/6208/6510 is released as Beta



Dear Grandstream Customers,

Firmware for UCM6202/6204/6208/6510 is now released as Beta. Here is the link for the release notes:

The firmware and release notes can be downloaded from:

Please contact us should you have any issues. Thank you for your support for Grandstream products.

Technical Support
Grandstream Networks, Inc.



Seems to have fixed my UCM 6510’s rebooting issues. System seems to handle high call volumes very well with good CPU and memory management.


Now just waiting for the ability to reset Call Queue Statistics each day instead of rebooting the system.


isn’t it comfortable to restart UCM? :stuck_out_tongue:


Been doing it for the last 6 months and still hold my breath each time.


@Telefonix have you seen any issues with this F/W? I have been studiously avoiding upgrades because of all the issues that have been reported along the way with previous 1.0.20.x releases. But seeing your rebooting issue seems to be fixed I’m thinking it might also fix the “hanging” issue I see on my 6208’s and 6204’s. Thanks for any insights you can provide.


If by hanging you mean orphan calls showing active on the Active Calls display, rebooting does solve that… I have fixing a symptom with a kludge, but it is up to Grandstream to fix the underlying problem.


@drostoker No, I mean actual box hang issues where the box itself becomes completely unresponsive. I have hung back on 1.0.19 because of all the issues I was seeing on the (earlier) 1.20 builds but maybe, now, it is time to move. I have said it before and I’ll say it again, I really wish Grandstream would put more effort into fewer but much more stable releases. I realize this is probably wishful thinking because EVERY vendor is pushing unstable, buggy code at their customers (yes, I am looking at YOU, Microsoft). But one can still “wish” for things. And as GS doesn’t charge for software support I guess you get what you pay for. I would almost welcome a paid support model if it meant more resources would go into testing and debugging code. Ok, there endeth the rant …


Thank you for the clarification.

IMHO it would improve matters if a GS person from each product group was given responsibility to monitor and respond to the related forums. There is too big a disconnect between those of us selling/installing/supporting products and the development team from my perspective.


I personally think it very stable and has settled down my most busiest and troublesome system.


There have been several fixes regarding system stability in this firmware. Additionally, should have addressed the lingering calls on the Active Calls page.


@GS.Jimmy thanks for this note. Sadly, I have users complaining of call quality issues since applying this firmware to UCM’s. Lots of comments like "calls just ring and ring (outbound), I can’t hear the other end of the call but they hear me, and so on and so forth. We haven’t changed any of our settings on the UCM’s, just applied the F/W update. We did have a few issues like this prior to the F/W update but now seems to be exacerbated. I am going to push F/W updates to the phones (most GXP2135’s) and see if that makes any difference. I have chatted with our carrier ( but they don’t see anything untowards at their end.


Could you please PM me network captures of the issues that include syslogs with PJSIP (all), PBX (all), and RTP (notice & debug)?

Regarding the outbound calls that just keep ringing, is even receiving these, or are the calls just trapped within the UCM?


@GS.Jimmy All calls reach They are doing a much deeper dive as I type this.


It will take me a bit to get set up for the log captures you have requested.


@GS.Jimmy has made some backend routing changes which they say should improve our call quality. I am thinking this is tacit admittance the problem is with them and not with our GS gear. I will keep you advised.


I’m having the same issue (same ITSP) but since 2 beta firmware versions back. I just installed this version and still having the issue. The issue is not 100% but frequent enough to annoy people.

The ITSP said “all good” but it raises questions since it was working fine for years.

Good to note that the issue is with just one customer out of many.


@cyfo Yah, they seem to play a bit fast and loose sometimes. They said they have played with routing but it doesn’t seem to have changed much to this point. I don’t have better luck with my flowroute link, either. But was brilliant until about 6 weeks back. Users yell because the “phones suck”. Oh and our number gets displayed as being from RWANDA to lots of folks, and has no good answer for that one. Yeesh.


That is my timing also, it started 6 weeks ago. But I’m not having the CID issue.

I even move to a “newer” server of theirs and nothing changed.

I’m currently capturing syslog as well.