Microsoft has released a cumulative update for Skype for Business Server 2015, Core Components. The version number of this update is 6.0.9319.886.
How to install the update
To install the cumulative update for Skype for Business Server 2015 core components, follow the steps that are described in Updates for Skype for Business Server 2015 (KB3061064).
Note
The Cumulative Server Update Installer applies all updates for the appropriate server role in one operation.
Prerequisites
There are no prerequisites for installing this cumulative update.
Registry information
To use one of the cumulative updates in this package, you don't have to make any changes to the registry.
Restart requirement
You may have to restart the computer after you apply this cumulative update.
Update replacement information
This cumulative update replaces the September 2026 cumulative update 6.0.9319.885 for Skype for Business Server 2015, Core Components (KB5123294).
Update package installation information
To apply this cumulative update, you must follow the steps that are described in Updates for Skype for Business Server 2015 (KB3061064) on computers that are running the following server roles:
- Skype for Business Server 2015, Standard Edition server
- Skype for Business Server 2015, Enterprise Edition - Front End server
- Skype for Business Server 2015, Edge server
- Skype for Business Server 2015, Director server
- Skype for Business Server 2015, Standalone Mediation server
- Skype for Business Server 2015, Persistent Chat Front End server
- Skype for Business Server 2015, Video Interop server
- Skype for Business Server 2015, Administration Tools
Removal information
You must uninstall all cumulative updates of core components that are at version 6.0.9319.55 or a later version before you uninstall the cumulative updates for Skype for Business Server 2015 (Front End server and Edge server) that are at 6.0.9319.55 or a later version. Otherwise, you won't be able to start the RTCSRV service.
To remove these cumulative updates, follow these steps:
Note We recommend that you refer to the instructions that are described in Updates for Skype for Business Server 2015 when you remove these cumulative updates.
Open Control Panel, and then select Program.
Select Installed Updates.
Uninstall all updates of core components that are at version 6.0.9319.55 or a later version:
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB5005359) at version 6.0.9319.619. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB5003605) at version 6.0.9319.606. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4603032) at version 6.0.9319.601. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4594637) at version 6.0.9319.598. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4564307)** at version 6.0.9319.591. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4558384)** at version 6.0.9319.580. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4518733) at version 6.0.9319.562. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4505400) at version 6.0.9319.559. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4487978) at version 6.0.9319.548. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4492303 ) at version 6.0.9319.544. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4464354) at version 6.0.9319.537. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4340903) at version 6.0.9319.534. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4075225) at version 6.0.9319.516. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4074705) at version 6.0.9319.514. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4036311) at version 6.0.9319.510. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB4012620) at version 6.0.9319.281. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3207502) at version 6.0.9319.277. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3199088) at version 6.0.9319.272. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3149226) at version 6.0.9319.259. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3134259) at version 6.0.9319.235. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3097644) at version 6.0.9319.102. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3098601) at version 6.0.9319.88. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3090687) at version 6.0.9319.72. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Core Components (KB3051958) at version 6.0.9319.55. Then, select Uninstall.
Uninstall the updates for Skype for Business Server 2015 (Front End server and Edge server) that are of version 6.0.9319.55 or a later version:
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB5005361) at version 6.0.9319.619. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4558385)** at version 6.0.9319.580. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4518735)** at version 6.0.9319.562. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4505401)** at version 6.0.9319.559. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4487979)** at version 6.0.9319.548. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4464355) at version 6.0.9319.537. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4340904) at version 6.0.9319.534. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4086059)** at version 6.0.9319.516. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4074701) at version 6.0.9319.514. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4036312) at version 6.0.9319.510. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB4012621) at version 6.0.9319.281. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3207506) at version 6.0.9319.277. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3199093) at version 6.0.9319.272. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3149227) at version 6.0.9319.259. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3134260) at version 6.0.9319.235. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3097645) at version 6.0.9319.102. Then, select Uninstall.
Press and hold (or right-click) Skype for Business Server 2015, Front End server (KB3061059) at version 6.0.9319.55. Then, select Uninstall.
File information
The global version of this cumulative update uses a Microsoft Windows Installer package to install the cumulative update. The dates and the times for these files are listed in Coordinated Universal Time (UTC) in the following table. When you view the file information, the date is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
After the update is installed, the global version of this update has the file attributes, or a later version of the file attributes, that are listed in the following table.
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Archdb.sql | Not applicable | 2,10,772 | 02-Sep-26 | Not applicable | |
| Archjobs.sql | Not applicable | 5,283 | 02-Sep-26 | 19:30 | Not applicable |
| Cdrdb.sql | Not applicable | 18,23,903 | 29-Oct-15 | 17:15 | Not applicable |
| Cdrjobs.sql | Not applicable | 8,787 | 02-Sep-26 | 19:30 | Not applicable |
| Component_gac_microsoft.rtc.internal.dll | 6.0.9319.885 | 1,85,144 | 17-Aug-26 | 21:38 | x86 |
| Component_gac_microsoft.rtc.internal.storage.dll | 6.0.9319.881 | 8,84,792 | 08-Aug-25 | 11:55 | x86 |
| Dbcommon.sql | Not applicable | 36,067 | 02-Sep-26 | 19:27 | Not applicable |
| Dbrtc.sql | Not applicable | 21,64,130 | 02-Sep-26 | 19:31 | Not applicable |
| File_bootstrapper.exe | 6.0.9319.102 | 2,78,720 | 17-Jul-26 | 15:29 | x64 |
| File_clseventres.dll.en_us | 6.0.9319.102 | 44,216 | 17-Jul-26 | 15:29 | Not applicable |
| File_csadditional.format.ps1xml | Not applicable | 81,294 | 17-Jul-26 | 15:29 | Not applicable |
| File_default.tmx | Not applicable | 2,69,92,799 | 23-Jul-25 | 10:43 | Not applicable |
| File_default.xml | Not applicable | 23,19,821 | 23-Jul-25 | 10:43 | Not applicable |
| File_gac_deviceupdate.dll | 6.0.9319.885 | 3,69,976 | 17-Aug-26 | 21:38 | x86 |
| File_gac_microsoft.identitymodel.clients.activedirectory.dll | 2.19.20802.213 | 1,89,728 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.identitymodel.clients.ad.windowsforms.dll | 2.19.20802.213 | 51,008 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.acd.common.dll | 6.0.9319.281 | 3,14,096 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.admin.authenticationhelper.dll | 6.0.9319.235 | 4,09,912 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.chat.endpoint.dll | 6.0.9319.548 | 12,09,088 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.client.psom.kernel.dll | 6.0.9319.516 | 1,06,752 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.collaboration.persistentchat.dll | 6.0.9319.510 | 3,94,544 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.collaborationnet.dll | 6.0.9319.259 | 49,94,312 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.applicationsharing.viewingnet.dll | 6.0.8886.52 | 4,12,496 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.applicationsharingnet.dll | 6.0.8886.52 | 1,70,296 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.clscommon.dll | 6.0.9319.852 | 4,92,952 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.collaboration.appsharing.dll | 6.0.9319.548 | 23,32,208 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.restapi.resourcemodel.dll | 6.0.9319.580 | 86,904 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.setup.xamluilib.dll | 6.0.9319.102 | 3,95,560 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.sipepsnet.dll | 6.0.9319.580 | 29,13,360 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.ucwa.clientmodel.dll | 6.0.9319.619 | 7,79,136 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.internal.ucwa.resourcecontract.dll | 6.0.9319.619 | 4,29,448 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.interop.user.dll | 6.0.9319.102 | 37,624 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.management.adconnect.dll | 6.0.9319.537 | 5,98,272 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.management.common.dll | 6.0.9319.514 | 4,21,112 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.management.dbsetup.dll | 6.0.9319.537 | 1,74,128 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.management.deployment.dll | 6.0.9319.852 | 26,71,040 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.management.dll | 6.0.9319.886 | 61,03,864 | 02-Sep-26 | 20:42 | x86 |
| File_gac_microsoft.rtc.rgs.data.dll | 6.0.9319.559 | 4,12,536 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.rgs.management.dll | 6.0.9319.869 | 3,38,352 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.server.infrastructure.dll | 6.0.9319.281 | 4,14,496 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.server.mcuinfrastructure.dll | 6.0.9319.534 | 27,65,968 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.server.udclib.dll | 6.0.9319.537 | 5,60,688 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.server.udcliteinterface.dll | 6.0.9319.272 | 22,312 | 17-Jul-26 | 15:29 | x86 |
| File_gac_microsoft.rtc.synthetictransactions.dll | 6.0.9319.619 | 23,89,904 | 17-Jul-26 | 15:29 | x86 |
| File_gac_servertransportadaptor.dll | 6.0.9319.548 | 1,61,840 | 17-Jul-26 | 15:29 | x64 |
| File_installcsdatabase.exe | 6.0.9319.537 | 2,44,464 | 17-Jul-26 | 15:29 | x86 |
| File_localocscmdlets.format.ps1xml | Not applicable | 5,02,399 | 17-Jul-26 | 15:29 | Not applicable |
| File_microsoft.rtc.management.core.dll | 6.0.9319.852 | 26,61,272 | 17-Jul-26 | 15:29 | x86 |
| File_microsoft.rtc.management.dbsetup.dll | 6.0.9319.537 | 1,74,128 | 17-Jul-26 | 15:29 | x86 |
| File_microsoft.rtc.management.deployment.bootstrapper.dll | 6.0.9319.623 | 3,80,304 | 17-Jul-26 | 15:29 | x64 |
| File_microsoft.rtc.management.dllhelp.xml.en_us | Not applicable | 1,16,40,673 | 17-Jul-26 | 15:30 | Not applicable |
| File_microsoft.rtc.management.update.dll | 6.0.9319.102 | 2,39,376 | 17-Jul-26 | 15:29 | x86 |
| File_microsoft.rtc.management.writableconfig.dll | 6.0.9319.852 | 22,58,824 | 17-Jul-26 | 15:29 | x86 |
| File_microsoft.rtc.rgs.management.dllhelp.xml.en_us | Not applicable | 4,53,280 | 17-Jul-26 | 15:30 | Not applicable |
| File_ocsrgscmdlets.format.ps1xml | Not applicable | 39,570 | 17-Jul-26 | 15:29 | Not applicable |
| File_ocstypes.ps1xml | Not applicable | 9,52,406 | 17-Jul-26 | 15:29 | Not applicable |
| File_psdcleanupscheduledtasknightlyrunconfig.xml | Not applicable | 4,064 | 17-Jul-26 | 15:30 | Not applicable |
| File_purgehealthmonitoringusertransactions.ps1 | Not applicable | 13,921 | 17-Jul-26 | 15:29 | Not applicable |
| File_remoteocscmdlets.format.ps1xml | Not applicable | 5,08,365 | 17-Jul-26 | 15:29 | Not applicable |
| File_reportdata.en_us.xml | Not applicable | 1,13,58,611 | 30-Oct-18 | 11:44 | Not applicable |
| File_reportsetup.exe | 6.0.9319.537 | 5,13,776 | 17-Jul-26 | 15:29 | x86 |
| File_rtcsres.dll_en_us | 6.0.9319.559 | 14,92,480 | 22-Jul-19 | 09:50 | Not applicable |
| File_skypeforbusiness_b8499a8b_4b90_43b8_a27e_3c4e7b292c44_helpinfo.xml | Not applicable | 1,788 | 17-Jul-26 | 15:30 | Not applicable |
| File_startup.ps1 | Not applicable | 16,057 | 17-Jul-26 | 15:29 | Not applicable |
| File_user.format.ps1xml | Not applicable | 49,279 | 17-Jul-26 | 15:29 | Not applicable |
| File_wrtcesproxy.dll | 6.0.9319.102 | 38,592 | 17-Jul-26 | 15:29 | x64 |
| File_xdseventres.dll_en_us | 6.0.9319.281 | 87,744 | 17-Jul-26 | 15:29 | Not applicable |
| Mgcsprocs.sql | Not applicable | 1,87,644 | 02-Sep-26 | 19:26 | Not applicable |
| Qoedb.sql | Not applicable | 8,94,983 | 02-Sep-26 | 19:31 | Not applicable |
| Qoejobs.sql | Not applicable | 8,472 | 02-Sep-26 | 19:31 | Not applicable |
| Rtcabdb.sql | Not applicable | 1,79,996 | 02-Sep-26 | 19:29 | Not applicable |
| Rtcabdb2016.sql | Not applicable | 1,80,044 | 02-Sep-26 | 19:29 | Not applicable |
| Rtcdb.sql | Not applicable | 1,95,034 | 02-Sep-26 | 19:21 | Not applicable |
References
Learn about the terminology that Microsoft uses to describe software updates.
Get the latest cumulative update for Skype for Business Server 2015.