What is the latest Skype for Business User-Agent string?

When using a client other than Skype for Business (formerly known as Lync) to connect with your Office 365 account, you’ll need to provide the Microsoft Lync servers with a user-agent string they recognize as an “acceptable” client. The reasoning behind this is surely to give you the best possible experience and not at all to lock out other messaging clients.

Personally, I use Pidgin with the third party plugin “pidgin-sipe” to connect with the Office 365 service. However, this will only work as long as an “acceptable” user-agent string is provided.

As of March 2019, Skype for Business 2016 identifies itself with the following user-agent string:

UCCAPI/16.0.11425.20024 OC/16.0.11425.20096

If you try to connect with an invalid user-agent string you’ll get the following message, which includes a link to download Skype.

CSeq: 6 REGISTER
Warning: 311 lcs.microsoft.com "http://go.microsoft.com/fwlink/?LinkID=213295"
Server: RTC/6.0

I’ll keep this information up to date as long as I have a valid Office 365 subscription.

Older entries:

ClientUser-Agent
Skype for Business 2016UCCAPI/16.0.11231.20066 OC/16.0.11231.20130
Skype for Business 2016UCCAPI/16.0.11126.20010 OC/16.0.11126.20132
Skype for Business 2016UCCAPI/16.0.11029.20045 OC/16.0.11029.20079
Skype for Business 2016UCCAPI/16.0.11001.20054 OC/16.0.11001.20074
Skype for Business 2016UCCAPI/16.0.10730.20030 OC/16.0.10730.2008
Skype for Business 2016UCCAPI/16.0.10325.20036 OC/16.0.10325.20082
Skype for Business 2016UCCAPI/16.0.9330.2087 OC/16.0.9330.2087
Skype for Business 2016UCCAPI/16.0.9126.2116 OC/16.0.9126.2116
Skype for Business 2016UCCAPI/16.0.9029.2167 OC/16.0.9029.2167
Skype for Business 2016UCCAPI/16.0.8827.2131 OC/16.0.8827.2131
Skype for Business 2016UCCAPI/16.0.8625.2055 OC/16.0.8625.2090
Skype for Business 2016UCCAPI/16.0.8229.2045 OC/16.0.8229.2073
Skype for Business 2016UCCAPI/16.0.8067.2032 OC/16.0.8067.2032
Skype for Business 2016UCCAPI/16.0.7766.5281 OC/16.0.7766.2047
Skype for Business 2016UCCAPI/16.0.6965.5308 OC/16.0.6965.2117
Skype for Business 2016UCCAPI/16.0.6965.5302 OC/16.0.6965.2105
Skype for Business 2016UCCAPI/16.0.6741.5312 OC/16.0.6741.2071
Skype for Business 2016UCCAPI/16.0.6741.5299 OC/16.0.6741.2056
Skype for Business 2016UCCAPI/16.0.6001.1078 OC/16.0.6001.1078
Skype for Business 2016UCCAPI/16.0.6001.1073 OC/16.0.6001.1073
Skype for Business 2016UCCAPI/16.0.6001.1061 OC/16.0.6001.1061
Skype for Business 2016UCCAPI/16.0.6001.1043 OC/16.0.6001.1043
Skype for Business 2015*UCCAPI/15.0.4823.1000 OC/15.0.4823.1000
Skype for Business 2015UCCAPI/15.0.4813.1000 OC/15.0.4809.1000
Skype for Business 2015UCCAPI/15.0.4805.1000 OC/15.0.4805.1001
Skype for Business 2015UCCAPI/15.0.4753.1000 OC/15.0.4753.1003

*= Current User-Agent from Skype for Business 2015
This page was last updated on Tuesday, March 19, 2019.

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Roger Comply
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