Microsoft released Cumulative Update 10 (July 2019) for Skype for Business 2015. The update includes many fixes but no new features.

– Update September 6th –
Due to problems with VVX phones there is a new release of this CU, CU 10 Hotfix 1. All links in this article points to that hotfix and not the old file.

Download

https://www.microsoft.com/en-us/download/details.aspx?id=47690

https://download.microsoft.com/download/F/B/C/FBC09794-2DB9-415E-BBC7-7202E8DF7072/SkypeServerUpdateInstaller.exe

Improvements

  • 4510852 UCWA client is disconnected because w3wp.exe crashes when using clarity connect in Skype for Business Server 2015
  • 4510851 SCOM SQL alerts are created every hour on SQL Secondary Replica server if “Always On” for Monitoring Server is set in Skype for Business Server 2015
  • 4510850 Skype for Business on Mac user’s latest photo can’t be seen until signing in to a Windows client in Skype for Business Server 2015
  • 4511313 “Too many outstanding requests for a single user” error occurs on Front-End servers in Skype for Business Server 2015
  • 4510847 Rate My Call on UCWA clients still shows after installing the January 2019 Cumulative Update for Skype for Business Server 2015
  • 4510846  “InstallDatabaseInternalFailure: An internal error has occurred…” error when installing new databases in Skype for Business Server 2015
  • 4507230 Support LBR and branch site voice resiliency conflicting requirements in Skype for Business Server 2015
  • 4459114 The installed local XDS database version doesn’t match the expected version in Skype for Business Server 2015
  • 4507232 Resuming a PSTN call that was put on hold results in one-way audio in Skype for Business Server 2015
  • 4510845 UCWA Event ID 20002, 20003, and 20033 occurs after you install the July 2018 cumulative update for Skype for Business Server 2015
  • 4510844 Can’t find the response group agent that’s synced from an existing distribution list in Skype for Business Server 2015
  • 4510843 Forwarding a missed call from Shared Line Appearance fails in Skype for Business Server 2015
  • 4507228 No notifications from UCMA conference subscriptions after a network disconnection in Skype for Business Server 2015
  • 4510842 Form-based authentication still works after you disable external basic authentication in Skype for Business Server 2015
  • 4510841 Skype for Business 2015 Mediation Server doesn’t respect the codec prioritization for outgoing PSTN calls
  • 4510840 Error ID 28042 and UCMA sign-in fails in Skype for Business Server 2015
  • 4510839 Skype for Business still rings if a PSTN call is ended before it’s answered by an online user in Skype for Business Server 2015
  • 4510855 Can’t edit interactive RGS workflows via the web interface in Skype for Business Server 2015
  • 4507233 Enterprise users can’t request control of an anonymous user’s shared screen in Skype for Business Server 2015
  • 4510856 User can’t create Skype meeting for a delegator via Skype for Business on Mac if they’re homed in different pools in Skype for Business Server 2015
  • 4512879 UCWA client can’t make a P2P call or join a conference when EnableExternalAccessCheck is True and EnableOutsideAccess is False in Skype for Business Server 2015
  • 4503584 “The Audio/Video Conferencing Server has failed to create a conference” error (ID 32005) occurs on Audio/Video Conferencing Server in Skype for Business Server 2015

More information
https://support.microsoft.com/en-us/help/3061064/updates-for-skype-for-business-server-2015