Since I originally authored this article, the behavior for the meeting invites has changed, with respect to the Join by phone section.


2016 MSI: https://support.microsoft.com/en-us/help/4042798/update-for-mobile-clients-to-join-pstn-calls-with-o...


2015 MSI: https://support.microsoft.com/en-us/help/4019641/update-for-mobile-clients-to-join-pstn-calls-with-o...


Click-to-Run (C2R): the behavior noted in the KBs above is available starting with version 16.0.8431.2046. However, the new format is enabled by default (in the MSI builds it is disabled and needs to be enabled with a registry value). To disable the behavior, create the OneTapJoinForPSTNCallingOnMobile registry entry (as noted in the above support articles) and set this to 0. NOTE: Disabling this will reset it back to a hyperlink, however it will not include the access code as part of the hyperlink.


When enabled, the new meeting invite looks as follows:




On the desktop, it is no longer a hyperlink; however, on mobile, it will render as a hyperlink. The user experience, from the mobile side, is outlined here: https://support.office.com/en-us/article/Join-a-Skype-for-Business-meeting-on-a-mobile-device-b19a0e...


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Based on feedback we’ve heard from our customers, we’ve made a few updates to Meeting Invites that are generated by the Skype for Business desktop client. In this blog post, we’ll focus on two new additions – the formatting of the dial-in string, and a link to join using the web app. Let’s take a look!


Join by Phone updates


In the meeting invite, the “Join by phone” section now creates hyperlinks for the dial-in numbers that includes a pause (the comma) followed by the Conference ID. This is especially useful when a user wants to join the conference using a mobile phone that doesn’t have the Skype for Business mobile app installed. When the hyperlink is clicked, it allows the dial-out to first dial the bridge number (1-866-679-9995), then pause, then send the Conference ID (75818576) through DTMF tones, completing with the pound (#) sign. The purpose here is to allow one-click join into the dial-in portion of the conference, without having to manually enter the conference ID.


The requirements for the formatting of the dial-in number as tel:<phone number>,<conference id># are as follows:

  1. For an online user (hosted in Office365), the meeting organizer needs a license for Cloud PSTN Conferencing (CPC). They also need to be leveraging Dynamic PSTN meetings.
  2. For an on-premises user, no requirements are needed server-side.
  3. Limitations on Outlook Client versions are as follows:
    • Outlook 2016 Click to Run (C2R) installs only. Minimum version 16.0.7369.2038 (Current Channel - October 2016).
    • Outlook 2016 MSI installs will not work.
    • Outlook 2013 C2R and MSI installs will not work.
    • The meeting needs to be created using Outlook Client. (Outlook Web App [OWA] won’t work)

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Meeting Join URLs
In addition to the formatting for Join by phone, we’ve added a hyperlink that allows joining directly using the Skype Web App. In this instance, the user would be able to participate in the meeting using the web application, even if they have the Skype for Business client installed locally. This is useful if the user is having difficulty joining the meeting using the full client. Many folks already know about this workaround, but for those that don’t, here’s a little background.




When you create a meeting, there is a meeting join URL that is constructed for the meeting, which looks like this: https://meet.lync.com/microsoft/bryanyce/RY1MVVR1, (this is hyperlinked as Join Skype Meeting in the invite) along with relevant dial-in information (such as the dial-in numbers, toll-free and toll if available) as well as the Conference ID.

If you focus on the meeting join URL, you can break it down as follows:

  • https://meet.lync.com/ -> this is the location of the meeting, also known as the Meet Simple URL. In this example, this is a meeting hosted in Office365.
  • /microsoft/bryanyce/ -> this is the company and organizer information. In this example, this is in the Microsoft tenant, and the organizer is me (bryanyce)
  • /RY1MVVR1 -> this is the Focus ID of the meeting

It’s important to understand that in the Online world, the meeting join URL is always a unique URL; meaning, the Focus ID of the meeting is always different. In the on-premises world, if you went into Meeting Options for the meeting, you would see this:



“My dedicated meeting space” means that the Focus ID would always be the same, for every meeting that you scheduled, so your join URLs would all be identical.

“A new meeting space” means that the Focus ID would be unique for every meeting.

However, when your account is hosted in Office365, you see this:




Notice that you don’t see the two radio buttons as before? That’s because in online, the behavior is always equivalent to “A new meeting space”. By the way, this also has nothing to do with the new Dynamic IDs feature that we enabled. That feature is specifically for the dial-in coordinates of the meeting (the conference ID), and not the meeting URL (which is why, after your tenant has been enabled for Dynamic IDs, you don’t see any change in the Meeting Options – some folks expected to get the radio buttons as we had on-premises, but that is not the case).

Join Skype Meeting updates
Now, with the history out of the way – what exactly did we do? Well, you can take that same meeting URL (https://meet.lync.com/microsoft/bryanyce/RY1MVVR1) and by simply appending ?sl=1 to the end, force the join launcher to use the Skype Web App, instead of trying to launch the full client. The URL ends up as https://meet.lync.com/microsoft/bryanyce/RY1MVVR1?sl=1 (which we show as “Try Skype Web App” in the invite) – allowing the user to go straight to the web client. This is helpful in situations where joining through the full client fails.



Occasional Visitor

Great features Bryan!  I was just talking with one of my users this week who was wondering if he could get a phone number + meeting ID clickable-link, so I'm glad that's something that's been added.  I'm a little confused by the requirements, though.  I have an Office 365 Exchange vNext mailbox, an on-premises Skype account, and Outlook 2016 C2R current channel.  I don't see the new features, unfortunately.  Is this not a supported scenario?  Would it be supported if my Skype account was in Office 365?

Occasional Visitor

Is there a way to format the on-prem dial in numbers to show sepearte lines for toll-free and toll numbers? Or is there a specific version of Sfb that allows new filed entries?

Not applicable

 These new features seem to meet a need but I have been puzzled as to why the online invites are so tightly tied to the versions of Outlook.  We would love to see the invite templated in SfB itself so that it didn't matter which version of Outlook is used to schedule the meeting.  It would then allow full customisation/corporate branding and the ability to add specific instructions to users.  e.g. we use Polycom RelaPresence and dialing in from one of the Legacy VC units alwasy seems to confuse our users.

Occasional Contributor

Glad to see, it's finally there!

https://support.microsoft.com/en-us/kb/3207069 (also for Lync 2013/Sfb 2015 clients)


There are so many technical pitfalls for users that want to join a meeting that it was overdue to have the ?sl=1 parameter in the meeting invite. Thanks!

New Contributor

I'm an on-premises Skype for Business user and the Trouble Joining Web App link didn't show up until I updated to the December build and Skype for Business showed 16.0.7571.7060.  November or October builds didn't work.

Occasional Visitor

Update from me.  I had the same experience as Elan.  When I forced the installation of the December Current Channel update I can now create calendar invites with these options.  I also am now running 16.0.7571.7060.

Frequent Visitor

Really nice to see this stuff coming to vanilla sfb invites at last. At the minute I use this tool to get single click to join links, customisation/corporate branding and the ability to add specific instructions to users into my invites. It doesn't matter which version of the Skype client you have either, or if you're on prem. Very handy!

Occasional Visitor

I agree with David, great to see this coming through. We also use the same tool as David which is pretty neat.

Frequent Contributor

Love the way you inform us of even the smallest changes you perform and why and let us comment here. Keep doing that!


1. Would it be possible for you to shorten the whitespace below between the number and the language since right now it kind of stands out to the right a bit much?


Reason is because for us, this whitespace is extremely large for some reason:




2. What's the purpose of adding "(Dial-in Number)"? Isn't that uneccesary information since above it says "Join by phone" and then of course it's a dial-in number.

Occasional Contributor

By the way, the additional Web App link looks nasty when used with German (non-english?) language packs. Seems that this was not very well tested. When setting the invite to english in the meeting options, the invite looks nice.






Is the ability to customize the meeting invitation (beyond the footer and help/legal links) anywhere on the roadmap?  It looks like 3rd party vendors have worked on that, but I don't need much in the way of bells/whistles like they are offering.




One of my user is not able to see the 'Try Skype Web App' option in his Skype Invites. The user is on following versions and when we click 'Update Now' then it gives the messages indicating that we are already on the latest version of Outlook:

Outlook: Microsoft Outlook 2016 MSO (16.0.7329.1047) 32-bit
Office: Microsoft Office 365 ProPlus Version 1609 (Build 7369.2120)


Thanks so much.




Hi Vivek, 7369.2120 is the Deferred Channel, and this feature likely hasn't reached that channel yet (that's the idea of Deferred, minimal feature updates). You can see the current channels/builds here: https://support.office.com/en-us/article/Version-and-build-numbers-of-update-channel-releases-ae9424...

Occasional Contributor

Hopefully, the well formatted invitation link in German (and other than English languages?) will make it into the next update of the current channel...


Occasional Visitor

Good Day. Is format dialing available only for Office 365 or should this also work with on-prem Skype for Business implementations?

Occasional Visitor



This was a great feature - I was one of the many customers in Australia requesting this feature - however by version 1705 (Build 8201.2102.CTR) it has already been broken.


So now my iPhone dials +bridgenr;confid    ie the comma has been replaced by a ; and the # is AWOL altogether.


The ; is bad news because it means the phone stops dialling until I hit a key, whereas with the comma it dialled immediately the call was connected. And the missing # ... well I can't think of any good reason for leaving that out.



Frequent Visitor

Why doesn't S4B have simple dial in strings like the competitors.  There needs to be a simple single click format in text like this:  1-555-1212,,12345678


The formatting of the current meeting notice looks horrible on an Iphone in native IOS calendar.  I know Microsoft wants their products to work on multiple platforms, and not having a single click dial string in a major limitation and so much less than their competitors have in their meeting notices.  (think Zoom)



Occasional Visitor

Michael, we have overcome this issue by using an app called CustomInvite from Modality Systems

Occasional Visitor

I can't find a way to change and format the dial-in number to tel:<phone number>,<conference id># 

Is this available for Office 365? is there a power shell command?

 any help would be greatly appreciated

Not applicable

It seems this update/feature was regressed in one of the recent updates.  Currently on SfB 16.0.8431.2046 (64-bit) & the dial-in number is no longer a link. 


Just updated from 16.0.7766.5281 (64-bit) where it was a link.


What happened?  When will this be re-enabled?


Or, as others have asked, allow for the admins to customize the templates holistically.

Occasional Visitor

thanks Ed Carson

your post really helped as i was searcing this from yesterday why suddenly link is not there


New Contributor

It seems that i got an Update to 16.0.8201.2200 64 Bit that disables this Feature. This is the current Build offered by Windows Insider Program.

I have set the registry Key OneTapJoinForPSTNCallingOnMobile=1 and have an Click 2 run Installation but that does not help. You state it will be availible on 16.0.8431.2046 Build, but this is not offered on regular Microsoft Update Services.


Anyway as stated best way wold be to offer a simple dial string   1-555-1212,,12345678 - any webex or competitor can do this and it always works well.


Any way to modify this release to make the dialstring work again to be joined by mobile?

Frequent Contributor

Fully agree to the above! The way it is now Microsoft could better rename the registry key to SevenTapJoinForPSTNCallingOnMobile.