August 2025 hotfix update 6.0.9319.881 for Skype for Business Server 2015, Core Components (KB5064902)

Microsoft has released a hotfix update for Skype for Business Server 2015, Core Components. The version number of this update is 6.0.9319.881.

Feature introduced in this update

Improvements and fixes

This update also fixes the issues that were previously listed in the following Microsoft Knowledge Base articles:

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 August 2023 cumulative update (6.0.939.853) for Skype for Business Server 2015, Core Components.

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.

  1. Open Control Panel, and then select Program.

  2. Select Installed Updates.

  3. 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.

  4. 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 19-Apr-20 04:10 Not applicable
Archjobs.sql Not applicable 5,283 21-Jul-19 22:35 Not applicable
Cdrdb.sql Not applicable 18,23,903 29-Oct-15 06:15 Not applicable
Cdrjobs.sql Not applicable 8,787 21-Jul-19 22:35 Not applicable
Component_gac_microsoft.rtc.internal.dll 6.0.9319.881 1,85,376 08-Aug-25 00:55 x86
Component_gac_microsoft.rtc.internal.storage.dll 6.0.9319.881 8,84,792 08-Aug-25 00:55 x86
Dbcommon.sql Not applicable 36,067 21-Jul-19 22:34 Not applicable
Dbrtc.sql Not applicable 21,64,130 21-Jul-19 22:35 Not applicable
File_bootstrapper.exe 6.0.9319.102 2,78,720 28-Oct-15 19:37 x64
File_clseventres.dll.en_us 6.0.9319.102 44,216 28-Oct-15 19:37 Not applicable
File_csadditional.format.ps1xml Not applicable 81,294 19-Jun-18 12:27 Not applicable
File_default.tmx Not applicable 2,69,92,799 22-Jul-25 23:43 Not applicable
File_default.xml Not applicable 23,19,821 22-Jul-25 23:43 Not applicable
File_gac_deviceupdate.dll 6.0.9319.601 3,66,456 25-Jan-21 22:48 x86
File_gac_microsoft.identitymodel.clients.activedirectory.dll 2.19.20802.213 1,89,728 04-Mar-21 21:34 x86
File_gac_microsoft.identitymodel.clients.ad.windowsforms.dll 2.19.20802.213 51,008 04-Mar-21 21:34 x86
File_gac_microsoft.rtc.acd.common.dll 6.0.9319.281 3,14,096 01-Apr-17 02:12 x86
File_gac_microsoft.rtc.admin.authenticationhelper.dll 6.0.9319.235 4,09,912 24-Feb-16 07:22 x86
File_gac_microsoft.rtc.chat.endpoint.dll 6.0.9319.548 12,09,088 08-Apr-19 10:06 x86
File_gac_microsoft.rtc.client.psom.kernel.dll 6.0.9319.516 1,06,752 27-Feb-18 07:13 x86
File_gac_microsoft.rtc.collaboration.persistentchat.dll 6.0.9319.510 3,94,544 10-Nov-17 11:50 x86
File_gac_microsoft.rtc.collaborationnet.dll 6.0.9319.259 49,94,312 14-Jun-16 15:20 x86
File_gac_microsoft.rtc.internal.applicationsharing.viewingnet.dll 6.0.8886.52 4,12,496 09-Feb-18 08:42 x86
File_gac_microsoft.rtc.internal.applicationsharingnet.dll 6.0.8886.52 1,70,296 09-Feb-18 08:42 x86
File_gac_microsoft.rtc.internal.clscommon.dll 6.0.9319.852 4,92,952 30-Jul-23 15:11 x86
File_gac_microsoft.rtc.internal.collaboration.appsharing.dll 6.0.9319.548 23,32,208 08-Apr-19 10:07 x86
File_gac_microsoft.rtc.internal.restapi.resourcemodel.dll 6.0.9319.580 86,904 18-Apr-20 17:03 x86
File_gac_microsoft.rtc.internal.setup.xamluilib.dll 6.0.9319.102 3,95,560 28-Oct-15 19:31 x86
File_gac_microsoft.rtc.internal.sipepsnet.dll 6.0.9319.580 29,13,360 18-Apr-20 17:04 x86
File_gac_microsoft.rtc.internal.ucwa.clientmodel.dll 6.0.9319.619 7,79,136 26-Jul-21 01:51 x86
File_gac_microsoft.rtc.internal.ucwa.resourcecontract.dll 6.0.9319.619 4,29,448 26-Jul-21 01:46 x86
File_gac_microsoft.rtc.interop.user.dll 6.0.9319.102 37,624 28-Oct-15 19:37 x86
File_gac_microsoft.rtc.management.adconnect.dll 6.0.9319.537 5,98,272 29-Oct-18 13:44 x86
File_gac_microsoft.rtc.management.common.dll 6.0.9319.514 4,21,112 10-Jan-18 23:07 x86
File_gac_microsoft.rtc.management.dbsetup.dll 6.0.9319.537 1,74,128 29-Oct-18 13:49 x86
File_gac_microsoft.rtc.management.deployment.dll 6.0.9319.852 26,71,040 30-Jul-23 15:10 x86
File_gac_microsoft.rtc.management.dll 6.0.9319.869 61,02,048 05-Oct-23 02:05 x86
File_gac_microsoft.rtc.rgs.data.dll 6.0.9319.559 4,12,536 21-Jul-19 11:46 x86
File_gac_microsoft.rtc.rgs.management.dll 6.0.9319.869 3,38,352 05-Oct-23 02:06 x86
File_gac_microsoft.rtc.server.infrastructure.dll 6.0.9319.281 4,14,496 01-Apr-17 02:20 x86
File_gac_microsoft.rtc.server.mcuinfrastructure.dll 6.0.9319.534 27,65,968 19-Jun-18 12:24 x86
File_gac_microsoft.rtc.server.udclib.dll 6.0.9319.537 5,60,688 29-Oct-18 13:48 x86
File_gac_microsoft.rtc.server.udcliteinterface.dll 6.0.9319.272 22,312 13-Oct-16 02:23 x86
File_gac_microsoft.rtc.synthetictransactions.dll 6.0.9319.619 23,89,904 26-Jul-21 01:45 x86
File_gac_servertransportadaptor.dll 6.0.9319.548 1,61,840 08-Apr-19 10:07 x64
File_installcsdatabase.exe 6.0.9319.537 2,44,464 29-Oct-18 13:53 x86
File_localocscmdlets.format.ps1xml Not applicable 5,02,399 30-Jul-23 15:09 Not applicable
File_microsoft.rtc.management.core.dll 6.0.9319.852 26,61,272 30-Jul-23 15:09 x86
File_microsoft.rtc.management.dbsetup.dll 6.0.9319.537 1,74,128 29-Oct-18 13:49 x86
File_microsoft.rtc.management.deployment.bootstrapper.dll 6.0.9319.623 3,80,304 01-Feb-22 12:01 x64
File_microsoft.rtc.management.dllhelp.xml.en_us Not applicable 1,16,40,673 19-Jun-18 23:17 Not applicable
File_microsoft.rtc.management.update.dll 6.0.9319.102 2,39,376 28-Oct-15 19:37 x86
File_microsoft.rtc.management.writableconfig.dll 6.0.9319.852 22,58,824 30-Jul-23 15:09 x86
File_microsoft.rtc.rgs.management.dllhelp.xml.en_us Not applicable 4,53,280 23-Oct-15 22:45 Not applicable
File_ocsrgscmdlets.format.ps1xml Not applicable 39,570 19-Jun-18 12:30 Not applicable
File_ocstypes.ps1xml Not applicable 9,52,406 30-Jul-23 15:09 Not applicable
File_psdcleanupscheduledtasknightlyrunconfig.xml Not applicable 4,064 19-Jun-18 23:17 Not applicable
File_purgehealthmonitoringusertransactions.ps1 Not applicable 13,921 19-Jun-18 12:27 Not applicable
File_remoteocscmdlets.format.ps1xml Not applicable 5,08,365 30-Jul-23 15:09 Not applicable
File_reportdata.en_us.xml Not applicable 1,13,58,611 30-Oct-18 00:44 Not applicable
File_reportsetup.exe 6.0.9319.537 5,13,776 29-Oct-18 13:53 x86
File_rtcsres.dll_en_us 6.0.9319.559 14,92,480 21-Jul-19 22:50 Not applicable
File_skypeforbusiness_b8499a8b_4b90_43b8_a27e_3c4e7b292c44_helpinfo.xml Not applicable 1,788 15-Jun-18 10:17 Not applicable
File_startup.ps1 Not applicable 16,057 26-Jul-21 01:46 Not applicable
File_user.format.ps1xml Not applicable 49,279 19-Jun-18 12:24 Not applicable
File_wrtcesproxy.dll 6.0.9319.102 38,592 28-Oct-15 19:35 x64
File_xdseventres.dll_en_us 6.0.9319.281 87,744 01-Apr-17 02:18 Not applicable
Mgcsprocs.sql Not applicable 1,87,644 10-Nov-17 04:26 Not applicable
Qoedb.sql Not applicable 8,94,983 30-Oct-18 00:42 Not applicable
Qoejobs.sql Not applicable 8,472 21-Jul-19 22:35 Not applicable
Rtcabdb.sql Not applicable 1,79,996 19-Jun-18 23:25 Not applicable
Rtcabdb2016.sql Not applicable 1,80,044 19-Jun-18 23:25 Not applicable
Rtcdb.sql Not applicable 1,95,034 19-Jun-18 23:21 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.