Zulu merge calls

I recieved a mailing from sangoma that it would be possible now to merge calls in Zulu. We are using the latest zulu version (3.4.0) but I can’t find this feature.
What am I missing?

Is anyone actually using Zulu?! Posted two (really basic informal) questions in a time span of a week and got 0 response …

Hello Benoit,

Sorry for the delay, yes there are customers actually using Zulu, but since this is a public forum (and not a support forum)… waiting less than 24 hours for a reply it doesn’t seem too crazy to me, please consider that.

The workflow should be the following:

  1. Ext A calls Ext B
  2. hold that call
  3. open the dialpad
  4. call Ext C
  5. when extension C pick up you will see an icon for call joining / merging

So make sure your server is on the latest version too!

If you require more assistance you will need to open a ticket with Sangoma support.


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That is definitely acceptable but I had a different question open for 5 days without a reaction so that’s why I started wondering. You replied there as well so thank you again for that.
In your example you refer to extensions, I suppose the procedure also works for external phone numbers?
What is the minimum version on the server side for the zulu module that needs to be installed? We are on


PS: I have a support contract and if I need configuration help or encounter an issue I’ll definitely open a support ticket. These questions are just about the functionality and would benefit the general community in my opinion.

Hello Benoit,

The minimum version on the server side for this feature is

In my example I am referring to extensions as we are adding support for inbound/outbound calls from/to external phones soon (not yet a release date, tho), Unfortunately this feature for inbound/outbound is not yet working properly (but we are adding support to this, soon).

Community members try to reply tickets as fast as we can in the forum, thanks for your patience :-).

Awesome, I highly appreciate your detailed answer!

Quick follow up question, our customer got the upgrade to for zulu today.
The call merge button is rather confusion because it visible and usable for external calls but it doesn’t work. Is that correct?
So it only works with 2 internal calls or does it also work for example when an external call was picked up and they want to add a co-worker with an internal extension to the call?

Since it’s been awhile, any status update on the Merge function? We’ve test Alpha v3.5.0 and Merge still does not function for external callers. This feature is typically required within all contact center environments and in my opinion should be a high priority fix to support remote work due to the COVID-19 situation.

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In the next days, we will be releasing that should fix some of the issues of merging calls, I will update this thread, then, thanks!

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@TedH and @digitalo Zulu Module was upgraded today to {14,15}.0.58.7 wanna upgrade and check that this issue should be resolved?


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I have tested and can confirm that this edge upgrade to will now allow to merge external calls.

However there seems to be an issue when adding a 4th call. One of the participants wasn’t able to receive the audio from the 4th call.
The 4th participant was able to hear everyone but with a very low volume.
Everything seems fine with only 3 participants.

Hello Philip,

Just to clarify, if you “rotate” the participants: is always the fourth (or the last you add) the one with issues? or is a specific user it seems to me that the very low volume is not related to zulu but something on the user end, want to clarify or do this test to confirm :slight_smile:


I did try to see if it was that specific user causing the issue. I replicated the same situation with the same users but in a different order. So the 4th user is now someone different and we still have this issue. It’s always the initial caller (also initializing the conference) using Zulu desktop that can’t hear the 4th participant. Unfortunately, I’m limited with licences right now and I always have the same user/endpoint as initial caller and Zulu application. So I can’t rule out this user/endpoint isn’t causing the issue.

I’ll get back to you next week, when I’ve had the chance to try this.


I couldn’t replicate your case but let’s wait until you can do more tests to see if we can figure something out.


I updated to 3.5.0.
I tried recreating the issue and I’m unable to recreate it. I’m not sure if it was the software version or other but at this point, I don’t really care. We’ll dig into it if ever it comes back.

Hi Guys. I updated my Zulu Server to and Using Zulu Client 3.5.0 but still can not merge 2 external calls.

Please let me know if there is anything I may be missing.


Are you using the Desktop client or Mobile client ? This feature isn’t available on the mobile client.

We use Zulu with 20 licenses and FreePBX. The Zulu desktop is a young product and will improve over time but other than the call-merge issue in this post no complaints.

That “merge calls” issue is resolved in 14/ can you test that version? thanks.

Thank you for responding, Angel. We are working to define the pattern and with multiple user combinations. That’s why we did not open a ticket. Zulu is impressive to our users, which is a miracle.

Should be able to provide more details next week. Hope that is okay.

Two examples where A, B and C are internal employees running Zulu desktop v3.5.0+206. Zulu Server 14.0.53. FreePBX 14.0.13.

Here is the pattern that fails and is repeatable:
A calls B and places a on hold.
A calls C and merges with B
B and C can hear each other but A cannot hear either B or C.

What does work:
A calls B
C calls A
A merges call and they can hear each other perfectly.