The Voice of O365 follows the Microsoft Lifecyle Update policy.
Current version: Skype for Business 2015 Enterprise March 2018 CU6HF2July 2019 CU10
Latest version: 
Compatability matrix
- Desktop clients: https://technet.microsoft.com/en-us/library/gg412781.aspx
- Mobile clients: https://technet.microsoft.com/en-us/library/dn951412.aspx
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- Critical
Critical updates to the platform will be done in the same evening to ensure the stability of the platform. These critical updates exclude feature updates. Critical fixes include hotfixes supplied by Microsoft. - Non-critical updates
Non-critical platform updates include feature updates and Skype for Business CU updates will be done in a cycle of release+1 month to ensure platform stability.
| Version | Cumulative Update | KB Article |
|---|---|---|
6.0.9319.559  | July 2019 (current) / CU10 | https://support.microsoft.com/kb/4505401 |
| 6.0.9319.548 | May 2019 / CU9 | https://support.microsoft.com/kb/4487979 |
| 6.0.9319.537 | January 2019 / CU8 | https://support.microsoft.com/kb/4464355 |
| 6.0.9319.534 | July/August 2018 / CU7 | https://support.microsoft.com/en-gb/help/3061064/updates-for-skype-for-business-server-2015 |
| 6.0.9319.516 |
| March 2018 / CU6HF2 | https://support.microsoft.com/en-us/help/3061064/updates-for-skype-for-business-server-2015 | |
| 6.0.9319.510 | December 2017 / CU6 | http://support.microsoft.com/kb/3061064 |
| 6.0.9319.281 | May 2017 / CU5 | http://support.microsoft.com/kb/4012621 |
| 6.0.9319.277 | February 2017 / CU4HF1 | http://support.microsoft.com/kb/3207506 |
| 6.0.9319.272 | November 2016 / CU4 | http://support.microsoft.com/kb/3199093 |
| 6.0.9319.259 | June 2016 / CU3 | http://support.microsoft.com/kb/3149227 |
| 6.0.9319.235 | March 2016 / CU2 | http://support.microsoft.com/kb/3134260 |
| 6.0.9319.102 | November 2015 / CU1 | http://support.microsoft.com/kb/3097645 |
| 6.0.9319.88 | September 2015 | http://support.microsoft.com/kb/3098601 |
| 6.0.9319.55 | June 2015 | http://support.microsoft.com/kb/3061059 |
| 6.0.9319.0 | RTM | NA |
Security updates
- Critical
Critical security updates will be peformed based on the severity status. Critical updates will be deployed within the upcoming certificate update window. Within those update windows the servers will be restarted and refreshed with the new updates. - Non-critical updates
Non-critical security updates will be performed every 2 weeks in the certificate update window.
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