Enable Lync 2010 Meeting Invite Template in Lync2013/SfB2015

The January 2017 client update for Lync 2013/SfB2015 includes a new registry key that allows Lync2013/SfB2015 Meeting Addin to create a meeting invite similar to the one in Lync 2010 client.

For reference we need to look how Dial in Conferencing Numbers are configured:

Get-CsDialInConferencingAccessNumber
https://technet.microsoft.com/en-us/library/gg413015.aspx

Now, before any change, we can see that a meeting invite for a user from the UK region will look like this:

After applying the January 2017 update KB3141468 for Lync2013/SfB2015 Client we can use the registry key EnableW14MeetingInvitationTemplate to have the template as Lync 2010 Meeting Add-in. We can simply add the registry key with Command Prompt or PowerShell:

Command Prompt:
reg add HKCUSoftwareMicrosoftOffice15.0LyncAddinPreference /v EnableW14MeetingInvitationTemplate /t REG_DWORD /d 1 /f

PowerShell:
Set-ItemProperty -Path 'HKCU:SoftwareMicrosoftOffice15.0LyncAddinPreference' -Name 'EnableW14MeetingInvitationTemplate' -Value '1' -Type DWord

Note: This registry key is only available on a User Level, we cannot add it under HKEY_Local_Machine.

Now we can create a meeting in Outlook and the invite will be similar to Lync 2010 Addin:

Please note that this registry key setting is only available for the Lync2013/SfB2015 (15.0.4893.1000 or later). The update list is available here:

Lync 2013/Skype for Business 2015 Client Update List
https://blogs.technet.microsoft.com/uclobby/2016/10/19/lync-2013-skype-for-business-2015-client-update-list/