Please Upgrade Immediately: Firmware for UCM6202/6204/6208/6510 Released as Official



Dear Grandstream Customers,

Firmware for UCM6202/6204/6208/6510 is now released as official. This firmware has added security improvement and it’s recommended to upgrade immediately.

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.



I have updated the firmware from version 19.XX to version 20.22 I cannot login
What is happening?



i´ve also updated to this firmware. Now the inbound blacklist works only for inserted numbers and anonymous calls won´t be blocked anymore. Has the insert method changed for inserting anonymous calls?

greetings MPi


you can read the changelog in the PDF:


Your answer do not help me! I´ve already viewed the changelog.

Actual manual: Enter a number in “Add Blacklist Number” field and then click to add to the list.Anonymous can also be added as a Blacklist Number <- and how should this be done now?

UCM hint: "In a blacklist rule, some characters have special meanings:

N ... Any digit from 2-9.
. ... Wildcard, matching one or more characters.
! ... Wildcard, matching zero or more characters immediately.
X ... Any digit from 0-9.
Z ... Any digit from 1-9.
- ... Hyphens are used mainly to improve readability and are not involved in pattern matching."

and? how do i block anonymous now?


I certainly can’t know that you’ve read the changelog if you don’t write it down.


Try to grab all normal calls by CallerID Pattern e.g. _+[12356789]. or whatever matches in your region.
Then make the same inbound route with no CID Pattern. This route should then match to all other inbound CIDs
which means also those who have none.


Thanks alot!

Your solution works perfectly for me. All calls without a number goes to IVR now and the IVR directly kills the call.


[VoIP Trunks] Increased the maximum limit of SIP trunks to 200
was waiting for this long time ago.


! … Wildcard should work with you.


hi @bvanmeter

Guys, we didn’t do it at all, I just updated the GRP2615 template and he for the umpteenth time deleted the custom template I created with 53 “P” added.
It’s not possible this thing, at least insert the possibility to export/import the custom templates, now I have to connect to all customers and recreate from scratch the GRP2515 template, then I’ll have to do the same when you update GRP2613 and so on …
It never happened with any GXP template, what explanation do you give?


i am having issues with the Zero Config /custom parameters in a UCM6208 latest firmware, after making a template and adding 25 custom parameters to the model config, when I go back to edit a parameter, they are all missing. GXP2170 is the model template. I have deleted it and made a new template 3 times, each timer the Custom Parameter P-codes are always missing. PLEASE FIX THE TEMPLATES and the rest of your security updates. I wish you would make a good firmware without all the video crap you added to the UCM, unnecessary in 99% of the installs.


I figured out more info on the DISAPPEARING CUSTOM PARAMETER P-CODES,
if you open the template and hit SAVE, without adding a new p code, they all disappear,
if you hit CANCEL, without adding a new p code, they are still there on re opening

anyway, remember to hit cancel if no changes were made, otherwise, good luck


actually there is an even bigger problem, if you update the GRP model the custom model disappears (very serious).


this is a great update, updated a ucm6208 last night now only the sim rings work, the other phones no longer ring if someone has a sim ring set up on their phone, this update is the worse i have seen. please fix. i guess its time to look at yealinks again… the grandstream road is not well made


who do we contact about all the issues with this update?


who is this, please add a phone number


Hey lincoln, they don’t have a phone number (at least maybe not for us “small guys”).

You can open a ticket there:

Be prepared, they will probably tell you to wait for a next release, and to downgrade if this issue is a showstopper for you.


calling the help desk is like asking my mom whats wrong with my truck