October 2025 GDK v2510.0.6194

October 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the October 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • October 2025 GDK
• Documentation

What's new in the October 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

October 2025 GDK

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of the SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

The Touch Adaptation Kit Command Line Tool (TAK CLI) (tak.exe) has been removed from the GDK setup. For instructions about how to download this tool, go to TAK CLI on GitHub.

Documentation

Offline documentation for the October 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.

October 2025 GDK Update 2 v2510.2.6247

October 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the October 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • October 2025 GDK Update 2
  • October 2025 GDK Update 1
  • October 2025 GDK
• Known issues
• Documentation

What's new in the October 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

October 2025 GDK Update 2

Notifications

Microsoft Azure PlayFab Party to v2.2.7 updates

• Changed the PartyNetwork::CreateEndpoint PartyStatusChangeResult behavior to return PartyServiceError for transient errors that occur before the token expires, and to return UserNotAuthorized only when the token has actually expired.
• Added audio device selection support for XUser-less or in-proc Gaming Runtime Services (GRTS) environments.
• Fixed a potential crash during multinetwork transition scenarios.

PlayFab Party to v1.10.16 updates

• The PartyNetwork::CreateEndpoint PartyStatusChangeResult behavior has been changed to return PartyServiceError for transient errors that occur before the token expires, and to return UserNotAuthorized only when the token has actually expired.
• Audio device selection support has been added for XUser-less or in-proc Gaming Runtime Services (GRTS) environments.
• A potential crash during multinetwork transition scenarios has been fixed.

Xbox services

Added support for enabling trace output to the debugger in the in-proc xgamingruntime, matching existing Gaming Runtime Services (GRTS) functionality.

To enable HTTP/WebSocket trace messages in the Visual Studio Output window, set the HKEY_LOCAL_MACHINE\Software\Microsoft\GamingServices\Auth\TraceToDebugger (REG_DWORD) registry key to 1. This setting is useful for debugging network issues, proxy configuration, and authentication problems. The feature is opt-in and has no impact when disabled.

Networking

XCurl has been updated to allow multiple calls to xcurl_global_init_mem() or curl_global_init_mem() between calls to curl_global_cleanup(). This new behavior matches the LibCurl behavior for curl_global_init_mem(), bringing the XCurl API in sync with LibCurl expectations. Additionally, curl_global_init(), curl_global_init_mem(), xcurl_global_init_mem(), and curl_global_cleanup() have been made thread safe.

packageutil compare Intelligent Delivery tag simulation fix

A logic error in packageutil compare caused Intelligent Delivery simulations to exclude required non‑OnDemand tags whenever any tag-based simulation was run. This produced inaccurate size and update predictions for titles using OnDemand or Feature-based packaging.

The fix ensures that:

• Non-OnDemand tags are always included in simulations for non-Feature packages.
• Feature-based packages are fully supported, including segmented tags and both full-feature and single-feature simulations.

This fix restores accurate size reporting and enables partners to correctly evaluate ID configurations.

Affected binary: PackageUtil.exe

Issue fixes

GDK tools

Fixed an issue that caused the GDK Command Prompts that are included in the GDK Tools installer to not properly include the GDK bin directory where the tools are located.

Fixed an issue that caused the XblTestAccountGui tool to fail to sign in with the following error message.

Live auth error: Login Error: The remote server returned an error: (400) Bad Request.

Fixed an issue that caused silent installations of the GDK that used the /features command-line switch to skip installing legacy layout components.

Microsoft Azure PlayFab Game Saves

Fixed an issue for FAIL_FAST on resume when a game uses PlayFab Game Saves.

Fixed an issue when using inproc PlayFab Games Saves where the device-contention callback could be incorrectly invoked when no actual device conflict occurred. Previously, the PlayFab SDK treated the absence of a pending manifest as proof that another device had taken over. However, this could also happen in normal scenarios (for example, when no sync was in progress or the local device completed its own upload). The SDK now correctly verifies whether the finalized manifest was actually created by a different device before triggering the contention callback, preventing false positive notifications to the game.

Fixed an issue where PlayFab Game Saves initialization failed on Gaming Runtime Services (GRTS) if the specified save folder directory didn't already exist, or if the provided path was missing a trailing backslash. The PlayFab SDK now automatically creates the directory if it's needed and ensures proper path formatting before initialization.

Fixed a synchronization issue where the inproc version of PlayFab Game Saves could incorrectly reuse an outdated pending manifest after the finalized cloud manifest version had already advanced past it. The pending manifest is now only reused when it both belongs to the current device and has a version greater than the finalized cloud version. This change prevents potential data inconsistencies during multi-device sync scenarios.

Fixed an issue where file modification time stamps were incorrect when synchronizing game saves between devices by using different storage providers (in-process versus Gaming Runtime Services (GRTS)). File time stamps are now properly preserved and converted to UTC when creating compressed archives, ensuring consistent time-stamp behavior across all platforms.

Fixed an issue where a Game Save description returned malformed/corrupted data on Steam Deck. Save descriptions are now properly Base64-decoded when they're retrieved from the manifest, ensuring that you get the correct human-readable description text that was originally set.

Fixed an issue when using inproc PlayFab Game Saves where canceling a sync operation from the progress dialog might cause an assert failure and unstable behavior. The cancellation mechanism has been redesigned to use a thread-safe atomic flag approach.

This change allows users to safely cancel ongoing upload or download operations from the progress UI without triggering race conditions or assertion failures. The SDK now properly checks for cancel requests during key stages of the sync operation and cleanly terminates with a user-canceled error code.

Fixed an issue when using inproc PlayFab Game Saves where downloading a large number of small files (for example, 1,000 or more small text files) would fail. The progress tracking was incorrectly using uncompressed file sizes for transfer progress reporting, which caused mismatches when dealing with many small, compressed files. Progress reporting now correctly tracks compressed byte sizes to accurately reflect actual network transfer progress.

Fixed a crash while using inproc PlayFab Game Saves that occurred when calling the PFGameSaveFilesSetSaveDescriptionAsync API while disconnected from the cloud. This API now returns an appropriate error code instead of crashing.

Fixed an issue in PFUninitializeAsync() where it would stop responding when using inproc PFGameSaveFiles when a sync failure callback was pending response during shutdown. The SDK now automatically cancels pending UI callbacks when uninitializing, ensuring clean shutdown even if the game doesn't respond to syncFailedCallback.

Fixed an issue where a game could crash when the active device was changed by using PlayFab Game Saves.

Fixed an issue where conflict callbacks displayed incorrect time stamps when using inproc PlayFab Game Saves.

Fixed an issue where PFGameSaveFilesSetSaveDescriptionAsync returned E_FAIL and subsequent calls stopped responding when called offline on Steam Deck.

Fixed an issue where canceling a failed upload on Steam Deck caused all subsequent uploads to permanently fail with E_PF_GAME_SAVE_MANIFEST_UPDATES_NOT_ALLOWED.

Fixed an issue where PFGameSaveFilesUploadWithUiAsync could hang indefinitely if a previous upload was canceled during a service error. The sync-failed UI callback is now correctly surfaced on retry, allowing the user to cancel or retry the operation.

Networking

Fixed an issue where 24 hours after the first lobby or matchmaking attempt, if the library hasn't been cleaned up, it might fail to create subsequent lobbies, join subsequent lobbies, subscribe to lobby invitations, or create subsequent matchmaking tickets.

Xbox services

Fixed an issue that caused game invite callbacks to not be fired on Steam Deck in the following two particular cases.

• When no Multiplayer Activity Connection String was provided with the invite
• When the invite handler was added by the title after the XUser had already been added

Fixed an issue where the in-proc gaming runtime didn't use WinHTTP proxy settings, causing E_XAL_NETWORK errors when a proxy (for example, Fiddler) was configured via netsh winhttp set proxy.

October 2025 GDK Update 1

Notifications

Cross-platform f...

October 2025 GDK Update 1 v2510.1.6224

October 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the October 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • October 2025 GDK Update 1
  • October 2025 GDK
• Known issues
• Documentation

What's new in the October 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

October 2025 GDK Update 1

Notifications

Cross-platform functionality

XUserSignOutAsync and XUserSignOutResult have been added to support player sign-out on Steam Deck. XUserIsSignOutPresent can be used to determine whether the current device supports sign-out via API.

Xbox services

Three new APIs—XGameInviteRegisterForPendingEvent, XGameInviteUnregisterForPendingEvent, and XGameInviteAcceptPendingInvite—have been added to restore consistency for XGameInvite callbacks, which previously behaved inconsistently across in-proc and out-of-proc scenarios. The new pending-invite handler is called only in in-proc flows. After the title handles invite acceptance, XGameInviteAcceptPendingInvite is called. This triggers the invite-accepted callback.

On Windows and Xbox console (where Gaming Runtime Services (GRTS) is available), shell UI was responsible for the invite acceptance flow. The title was notified only when the invite was accepted. For in-proc scenarios, such as Steam Deck, titles handle invite acceptance. The XGameInvite callback fires when an invite is received so that titles can manage the acceptance flow.

Microsoft Azure PlayFab Game Saves

Upload progress tracking now reports compressed byte counts. This change keeps progress callbacks and telemetry aligned with the actual data streamed and prevents premature "completed" percentages when large saves compress poorly.

The previously dormant PFGameSaveFilesAddUserOptions::RollbackToLastKnownGood and RollbackToLastConflict flags have been enabled. They now honor rollback requests during PFGameSaveFilesAddUserWithUiAsync. Titles get the expected selection instead of always syncing to the latest save.

Initialization now cleans up correctly after E_INVALIDARG failures (such as a missing Steam Deck save path). This change ensures that subsequent calls no longer report "already initialized."

Logging was added to improve diagnostics when running out-of-process.

Issue fixes

Microsoft Azure PlayFab Party

Fixed an issue where PlayFab Party voice chat couldn't be established when no XUser was signed in, including on Steam games played on Windows without an Xbox network user and on Steam Deck.

Xbox services

Fixed an issue where the URI received by the game from XGameInvite callbacks on Steam Deck didn't match the URI received on Windows. The Steam Deck URI only included the connection string but was missing the sender information and invited user XUID.

October 2025 GDK

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of the SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

The Touch Adaptation Kit Command Line Tool (TAK CLI) (tak.exe) has been removed from the GDK setup. For instructions about how to download this tool, go to TAK CLI on GitHub.

Known issues

XUserResolveIssueWithUiAsync flow

Issue:
The XUserResolveIssueWithUiAsync API is intended to resolve user account issues such as token or consent problems, not to change the signed-in identity. However, it's possible for a user who originally signed in with Account A to complete this flow and sign in with Account B, resulting in a different XUID.

Impact:
When the account changes during this flow, the API detects the mismatch and automatically fails the operation.

Applies to:

• October 2025 GDK
• October 2025 GDK Update 1

Guidance:
If the operation fails because of an account change, remove the user and re-add the user to ensure proper sign-in.

Downloading compressed save data

Issue:
PlayFab Game Saves might encounter issues when downloading compressed save data that's larger than its uncompressed size. This is most commonly encountered when a game is using its own file compression in addition to PlayFab Game Saves.

Applies to:

• October 2025 GDK
• October 2025 GDK Update 1

Guidance:
Consider disabling additional file compression, if possible.

Status:
This will be fixed in a future GDK update.

XblTestAccountGui tool test account error

Issue:
The XblTestAccountGui tool might fail to sign in test accounts. If so, the following error message appears.

Live auth error: Login Error: The remote server returned an error: (400) Bad Request.

Applies to:

• October 2025 GDK
• October 2025 GDK Update 1

Status:
This issue is corrected in the latest GitHub release of the Xbox Live developer tools. They're available at https://aka.ms/xbltools. This fix will be included in a future GDK release.

XGameInviteRegisterForPendingEvent must be called before adding XUsers

Issue:
On Steam Deck, XGameInviteRegisterForPendingEvent must be called before adding XUsers, or they won't be properly registered for invite notifications. This sequencing requirement was unintentional.

Applies to:
October 2025 GDK Update 1

Status:
This issue will be fixed in a future GDK release.

XGameInviteRegisterForPendingEvent requires connectionString to be set

Issue:
On Steam Deck, XGameInviteRegisterForPendingEvent won't invoke title callbacks for invites that are missing the Xbox Multiplayer Activity (MPA) connectionString. Although it's an optional field when sending the invite, XGameRuntime drops invite payloads without it.

Applies to:
October 2025 GDK Update 1

Workaround:
Provide a non-empty connection string when sending the invite. Ignore it on the receiving end if it isn't needed.

Status:
This issue will be fixed in a future GDK release.

Documentation

Offline documentation for the October 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.

October 2024 GDK Update 5 v2410.5.1966

October 2024 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the October 2024 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • October 2024 GDK Update 5
  • October 2024 GDK Update 4
  • October 2024 GDK Update 3
  • October 2024 GDK Update 2
  • October 2024 GDK Update 1
  • October 2024 GDK
  • Known issues
• Documentation

What's new in the October 2024 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

October 2024 GDK Update 5

Issue fixes

Xbox services

Fixed an issue where a crash was caused by a rare race condition during Real-Time Activity (RTA) disconnect and/or unsubscribe.

October 2024 GDK Update 4

Notifications

Networking

The XCurl default receive buffer size has been increased from 8 KB to 16 KB and improves the download speed of large requests. This new buffer size now matches that of LibCurl.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

October 2024 GDK Update 3

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio 2022 or when calling MiniDumpWriteDump from within the title.

The following error was previously displayed.

Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed.

October 2024 GDK Update 2

Issue fixes

Xbox services

Fixed an issue where MultiplayerManager resources weren't cleaned up when XblCleanupAsync was called during an ongoing multiplayer request.

October 2024 GDK Update 1

Notifications

Networking

The version of Microsoft PlayFab Party that's included in the GDK has been updated to v1.10.5. You can view the release notes at PlayFab Party Release Notes - PlayFab | Microsoft Learn.

Issue fixes

Media

Fixed an issue that caused the title to stop responding upon source reader termination. This was caused by Media Foundation Transform (MFT) samples being freed without waiting on pending fences.

October 2024 GDK

Breaking changes

System

Beginning with the October 2024 GDK release, the directory layout of the various extension libraries (for example, XSAPI, XCURL, GameChat, and PlayFab) has been modified to shorten the overall path length and simplify use in custom build systems. These changes are automatically handled by MSBuild rules for those customers who are using the Gaming.*.x64 GDK build platforms. No changes are required in these scenarios.

The changes between March 2024 and August 2024 are described by the following string substitutions.

• "DesignTime\CommonConfiguration\neutral\ExtensionLibrary.props" is now "ExtensionLibrary.props"
• "DesignTime\CommonConfiguration\neutral\Include" is now "Include"
• "DesignTime\CommonConfiguration\neutral\Lib" is now "Lib\x64"
• "Redist\CommonConfiguration\neutral" is now "Redist\x64"

GDK tools

Support for using the Visual Studio 2017 IDE for game development was removed in the October 2022 GDK. Support for building games with the Visual Studio 2017 toolset (v141) remained in place for use with Visual Studio 2019 and Visual Studio 2022 to ease the transition to a newer toolset.

Beginning with the October 2024 GDK, support for building with the v141 toolset will be removed. Note that versions of the GDK prior to October 2024 will continue to support building with the v141 toolset.

Microsoft Azure PlayFab

In the PlayFab Economy inventory redemption APIs, PFInventoryRedemptionSuccess and PFInventoryRedemptionFailure responses now return marketplaceAlternateId instead of offerId.

Customers who use these APIs must update their code to use the new marketplaceAlternateId field.

Notifications

Multiplayer

• Improved internal diagnostics.
• Updated PFMultiplayerCreateServerBackfillTicket to automatically handle failures where a match member is already a member of too many tickets. In this situation, the SDK automatically cancels existing tickets for members of the backfill ticket and retries ticket creation.

Issue fixes

Multiplayer

• Fixed an issue for the Xbox October 20024 GDK where some events wouldn't be queued after suspending and resuming a title.
• Fixed an issue for the Xbox October 2024 GDK that caused a crash after suspending and resuming a title.
• Fixed an issue where the internal PubSub notification WebSocket was slow to detect and react to disconnects. This could lead to errors when creating or joining lobbies and matchmaking tickets.
• Fixed an issue where failure of PubSub to establish a connection with the SignalR service wouldn't trigger a failed state change and wouldn't allow subsequent Multiplayer API calls to subscribe to PubSub.

Media

Fixed an issue that caused the title to stop responding because of incorrect fence waits. This occurred during Source Reader shutdown with High Efficiency Video Coding (HEVC) video playback.

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the October 2024 GDK Update 3.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed.

Applies to the following:

• April 2025 GDK
• October 2024 Update 1 GDK and Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

A fix to enable heap dumps to be completely written from Visual Studio will be made in future GDK updates.

GDK tools

In Visual Studio 2019, opening the GDK Help file by using the "?" button from the Xbox Gaming Explorer or any other Xbox tool windows in Visual Studio 2019 causes the GDK Help file to open to its overview page. This occurs rather than the topic page opening that's specific to the tool being used. This issue doesn't occur when using Visual Studio 2022.

Documentation

Offline documentation for the October 2024 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at http://aka.ms/gdkonline.

April 2026 GDK v2604.0.7822

April 2026 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the April 2026 Microsoft Game Development Kit with Xbox Extensions (GDKX) and the public GDK release. You can use the GDKX to develop games that can be certified and approved for release on Windows 11 PCs, Windows 10 PCs, Xbox One, and Xbox Series X|S consoles by using a shared codebase. For the GDK, you can develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

GDKX

• The April 2026 GDKX can be installed side-by-side with GDKXs from November 2019 and later.
• You can download GDKX releases from https://aka.ms/gdkdl.
• The release notes for all GDKX releases are at https://aka.ms/gdkreleasenotes.

GDK

• You can download GDK releases and view their release notes at https://aka.ms/gdk-winget.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • April 2026 GDK
• Known issues
• Documentation

NOTE: Release notes have a number after their descriptions, such as [12345678]. For GDKX users, this number represents an internal ID that Microsoft uses to track the work and history relating to the item. This number can be useful to your developer account manager if you have questions about a particular release note.

---

What's new in the April 2026 Microsoft Game Development Kit

• The GDKX and the GDK are released in two types: Major (focused on features, twice a year) and Updates (focused on fixes, as often as needed by partners).
• To view the full What's new section, see the online version of What's new.
• To view release notes for previous versions, for the GDKX, see release notes posts on the GDK forums. For the GDKX and the GDK, you can view the release notes in the online documentation at GDK release notes.

---

April 2026 GDK

Notifications

API deprecations

The XGameActivation API has replaced the XGameProtocol and XGameInvite APIs, providing a single API surface for all game activation scenarios. As a result, XGameProtocol and XGameInvite are now deprecated. Existing implementations will continue to function, but we recommend migrating to XGameActivation for new development and future compatibility.

The following APIs have been deprecated.

• XGameProtocolRegisterForActivation
• XGameProtocolUnregisterForActivation
• XGameInviteRegisterForEvent
• XGameInviteUnregisterForEvent
• XGameInviteRegisterForPendingEvent
• XGameInviteUnregisterForPendingEvent
• XGameInviteAcceptPendingInvite

For more information, see XGameActivation.

[61232139]

Developer tools

Mainstream support for Visual Studio 2019 has expired. Extended support continues until April 2029. For more information about Visual Studio 2019 product lifecycle and servicing, see Visual Studio 2019 Product Lifecycle and Servicing.

Visual Studio 2019 and the v142 toolset compiler are out of mainstream support as of April 2024 and are only getting security servicing. Support for Visual Studio 2019 integration and use of the v142 platform toolset via Visual Studio 2022/Visual Studio 2026 will be removed in a future release of the GDK. This process will include the removal of the Microsoft.Xbox.Services.142.GDK.C.lib library. For Visual Studio 2022 and Visual Studio 2026, we recommend moving to Microsoft.Xbox.Services.143.GDK.C.lib, which was added in the April 2026 GDK.

[61594513]

Address Sanitizer (ASAN) for Xbox is no longer supported on Visual Studio 2019. [60868415]

Screen captures can now be copied to the clipboard from the Xbox Manager Media Capture tab. [41667882]

PC command-line tools such as wdcapture, wdcapturesession, and xblpcsandbox now support direct bug feedback submission through the Feedback Hub app. [60250549]

Package Uploader now supports federated credentials. [60771527]

Microsoft Azure PlayFab

PlayFab Multiplayer has been updated to v1.9.0. For details, see PlayFab Multiplayer C++ SDK Release Notes - PlayFab | Microsoft Learn. [61288995]

Microsoft Azure PlayFab Party

PlayFab Party has been updated to v1.10.18. For details, see PlayFab Party Release Notes - PlayFab | Microsoft Learn. [61288995]

Issue Fixes

Fixed an issue that caused the language setting in a non-English command prompt to change to English after running GDK Xbox command-line tools such as xbapp.exe or xbconnect.exe. [59688191]

Fixed an issue where Xbox Game Package Manager didn't populate the UI with the last selected branch. [60771527]

---

Known issues

makepkg2: /priorpackage doesn't generate a compare report for MSIXVC2 packages

Issue:
In makepkg2, using the /priorpackage flag when packing MSIXVC2 packages doesn't generate a compare report. Compare report generation isn't supported for MSIXVC2 packages in this release.

Applies to:

• April 2026 GDK

Workaround:
None at this time.

Status:
This issue will be fixed in a future GDK update.

[61771743]

makepkg2: layout.xml requires DisplayName on all features

Issue:
In makepkg2, the layout.xml parser requires the DisplayName attribute on all features, including hidden features where a display name isn't meaningful.

Applies to:

• April 2026 GDK

Workaround:
Add a placeholder DisplayName attribute to any hidden features in layout.xml.

Status:
This issue will be fixed in a future GDK update.

[61767246]

makepkg2: /contentid flag fails when ContentId is absent from MicrosoftGame.config

Issue:
In makepkg2, using the /contentid flag when no ContentId is specified in MicrosoftGame.config results in the following error.

/contentid specified on the command line does not match the ContentId derived from the MicrosoftGame.config file.

This behavior differs from makepkg, which accepted the /contentid value directly in this scenario.

Applies to:

• April 2026 GDK

Workaround:
Use /contentidoverride instead of /contentid.

Status:
This issue will be fixed in a future GDK update.

[61767256]

MSIXVC2 packages can't be uploaded to Microsoft Partner Center via its web UI

Issue:
The upload of an .msixvc package to Partner Center fails if it was built by using the new makepkg2 tools.

Applies to:

• Partner Center web UI

Workaround:
Use one of the following tools to upload MSIXVC2 packages to Partner Center.

• makepkg2 upload command: makepkg2 upload /d <content_directory> /branch "<BranchName>" /msixvc2

• Xbox Game Package Manager: Download the latest version from https://github.com/microsoft/PackageUploader.

Status:
Partner Center will be updated in the coming months to add support for web uploads of MSIXVC2 packages.

XboxPcTray.exe might block MSIXVC2 package uninstall or update

Issue:
XboxPcTray.exe sometimes retains a handle to the game's Content folder, which can prevent uninstall or update operations from completing.

Applies to:

• April 2026 GDK

Workaround:
Close the Xbox PC Tray app before attempting to uninstall or update. To close it, right-click the XboxPcTray icon in the system tray, and then select Quit. You can also end the XboxPcTray.exe process in Task Manager.

Status:
This issue will be fixed in a future GDK update.

[61618609]

MSIXVC2 packages can't be uploaded via Package Uploader

Issue:
Uploading an .msixvc package to Partner Center via the Package Uploader command-line tool fails with a 400 (Bad Request) error if the package was built by using the makepkg2 tool with the /msixvc2 flag. Although MSIXVC and MSIXVC2 packages share the same .msixvc file extension, MSIXVC2 packages use a different internal format that Package Uploader doesn't currently support.

Applies to:

• Package Uploader CLI (PackageUploader.exe)

Workaround:
Use one of the following tools to upload MSIXVC2 packages.

• makepkg2 upload command: makepkg2 upload /d <content_directory> /branch "<BranchName>" /msixvc2>
• Xbox Game Package Manager: Download the latest version from https://github.com/microsoft/PackageUploader.

Status:
This issue will be addressed in a future release of Package Uploader.

MSIXVC2 packages in Partner Center appear as 1 byte in size in its UI

Issue:
Partner Center shows an incorrect size for uploaded MSIXVC2 packages...

April 2025 GDK Update 5 v2504.5.4125

April 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the April 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • April 2025 GDK Update 5
  • April 2025 GDK Update 4
  • April 2025 GDK Update 3
  • April 2025 GDK Update 2
  • April 2025 GDK Update 1
  • April 2025 GDK
• Known issues
• Documentation

What's new in the April 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

April 2025 GDK Update 5

Notifications

Microsoft Azure PlayFab Party to v1.10.16 updates

• The PartyNetwork::CreateEndpoint PartyStatusChangeResult behavior has been changed to return PartyServiceError for transient errors that occur before the token expires, and to return UserNotAuthorized only when the token has actually expired.

• Audio device selection support has been added for XUser-less or in-proc Gaming Runtime Services (GRTS) environments.

• A potential crash during multinetwork transition scenarios has been fixed.

Networking

XCurl has been updated to allow multiple calls to xcurl_global_init_mem() or curl_global_init_mem() between calls to curl_global_cleanup(). This new behavior matches the LibCurl behavior for curl_global_init_mem(), bringing the XCurl API in sync with LibCurl expectations. Additionally, curl_global_init(), curl_global_init_mem(), xcurl_global_init_mem(), and curl_global_cleanup() have been made thread safe.

packageutil compare Intelligent Delivery tag simulation fix

A logic error in packageutil compare caused Intelligent Delivery simulations to exclude required non‑OnDemand tags whenever any tag‑based simulation was run. This produced inaccurate size and update predictions for titles using OnDemand or Feature-based packaging.

This fix ensures that:

• Non‑OnDemand tags are always included in simulations for non‑Feature packages.

• Feature-based packages are fully supported, including segmented tags and both full‑feature and single‑feature simulations.

This fix restores accurate size reporting and enables partners to correctly evaluate ID configurations.

Affected binary: PackageUtil.exe

Issue fixes

GDK tools

Fixed an issue that caused the XblTestAccountGui tool to fail to sign in with the following error message.

"Live auth error: Login Error: The remote server returned an error: (400) Bad Request."

April 2025 GDK Update 4

Issue fixes

Xbox services

Fixed an issue where a crash was caused by a rare race condition during Real-Time Activity (RTA) disconnect and/or unsubscribe.

April 2025 GDK Update 3

Notifications

Networking

The XCurl default receive buffer size has been increased from 8 KB to 16 KB and improves the download speed of large requests. This new buffer size now matches that of LibCurl.

GDK tools

The build ID and content ID are both now available in the output data when running wdapp.exe /list /d and wdapp.exe /listdlc /d on a PC.

April 2025 GDK Update 2

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

April 2025 GDK Update 1

Notifications

GDK tools

Display IDs are now available by running the list-displays command in wdCapture to specify which display to capture.

Media

The XAppCaptureCancelUserRecord API has been added. It allows recordings that were started by XAppCaptureStartUserRecord to be stopped without the recording being saved.

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error was previously displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Fixed an issue in makepkg.exe that will, in the future, allow developers to upload packages with localized display names.

Xbox services

Fixed an issue that could cause high service loads because of Real-Time Activity resyncs.

April 2025 GDK

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the April 2025 GDK Update 1.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Applies to the following:

• April 2025 GDK
• October 2024 GDK Update 1 and October 2024 GDK Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

Documentation

Offline documentation for the April 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.

April 2025 GDK Update 4 v2504.4.4108

April 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the April 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • April 2025 GDK Update 4
  • April 2025 GDK Update 3
  • April 2025 GDK Update 2
  • April 2025 GDK Update 1
  • April 2025 GDK
• Known issues
• Documentation

What's new in the April 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

April 2025 GDK Update 4

Issue fixes

Xbox services

Fixed an issue where a crash was caused by a rare race condition during Real-Time Activity (RTA) disconnect and/or unsubscribe.

April 2025 GDK Update 3

Notifications

Networking

The XCurl default receive buffer size has been increased from 8 KB to 16 KB and improves the download speed of large requests. This new buffer size now matches that of LibCurl.

GDK tools

The build ID and content ID are both now available in the output data when running wdapp.exe /list /d and wdapp.exe /listdlc /d on a PC.

April 2025 GDK Update 2

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

April 2025 GDK Update 1

Notifications

GDK tools

Display IDs are now available by running the list-displays command in wdCapture to specify which display to capture.

Media

The XAppCaptureCancelUserRecord API has been added. It allows recordings that were started by XAppCaptureStartUserRecord to be stopped without the recording being saved.

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error was previously displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Fixed an issue in makepkg.exe that will, in the future, allow developers to upload packages with localized display names.

Xbox services

Fixed an issue that could cause high service loads because of Real-Time Activity resyncs.

April 2025 GDK

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the April 2025 GDK Update 1.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Applies to the following:

• April 2025 GDK
• October 2024 GDK Update 1 and October 2024 GDK Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

Documentation

Offline documentation for the April 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.

October 2024 GDK Update 4 v2410.4.1946

October 2024 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the October 2024 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • October 2024 GDK Update 4
  • October 2024 GDK Update 3
  • October 2024 GDK Update 2
  • October 2024 GDK Update 1
  • October 2024 GDK
  • Known issues
• Documentation

What's new in the October 2024 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

October 2024 GDK Update 4

Notifications

Networking

The XCurl default receive buffer size has been increased from 8 KB to 16 KB and improves the download speed of large requests. This new buffer size now matches that of LibCurl.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

October 2024 GDK Update 3

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio 2022 or when calling MiniDumpWriteDump from within the title.

The following error was previously displayed.

Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed.

October 2024 GDK Update 2

Issue fixes

Xbox services

Fixed an issue where MultiplayerManager resources weren't cleaned up when XblCleanupAsync was called during an ongoing multiplayer request.

October 2024 GDK Update 1

Notifications

Networking

The version of Microsoft PlayFab Party that's included in the GDK has been updated to v1.10.5. You can view the release notes at PlayFab Party Release Notes - PlayFab | Microsoft Learn.

Issue fixes

Media

Fixed an issue that caused the title to stop responding upon source reader termination. This was caused by Media Foundation Transform (MFT) samples being freed without waiting on pending fences.

October 2024 GDK

Breaking changes

System

Beginning with the October 2024 GDK release, the directory layout of the various extension libraries (for example, XSAPI, XCURL, GameChat, and PlayFab) has been modified to shorten the overall path length and simplify use in custom build systems. These changes are automatically handled by MSBuild rules for those customers who are using the Gaming.*.x64 GDK build platforms. No changes are required in these scenarios.

The changes between March 2024 and August 2024 are described by the following string substitutions.

• "DesignTime\CommonConfiguration\neutral\ExtensionLibrary.props" is now "ExtensionLibrary.props"
• "DesignTime\CommonConfiguration\neutral\Include" is now "Include"
• "DesignTime\CommonConfiguration\neutral\Lib" is now "Lib\x64"
• "Redist\CommonConfiguration\neutral" is now "Redist\x64"

GDK tools

Support for using the Visual Studio 2017 IDE for game development was removed in the October 2022 GDK. Support for building games with the Visual Studio 2017 toolset (v141) remained in place for use with Visual Studio 2019 and Visual Studio 2022 to ease the transition to a newer toolset.

Beginning with the October 2024 GDK, support for building with the v141 toolset will be removed. Note that versions of the GDK prior to October 2024 will continue to support building with the v141 toolset.

Microsoft Azure PlayFab

In the PlayFab Economy inventory redemption APIs, PFInventoryRedemptionSuccess and PFInventoryRedemptionFailure responses now return marketplaceAlternateId instead of offerId.

Customers who use these APIs must update their code to use the new marketplaceAlternateId field.

Notifications

Multiplayer

• Improved internal diagnostics.
• Updated PFMultiplayerCreateServerBackfillTicket to automatically handle failures where a match member is already a member of too many tickets. In this situation, the SDK automatically cancels existing tickets for members of the backfill ticket and retries ticket creation.

Issue fixes

Multiplayer

• Fixed an issue for the Xbox October 20024 GDK where some events wouldn't be queued after suspending and resuming a title.
• Fixed an issue for the Xbox October 2024 GDK that caused a crash after suspending and resuming a title.
• Fixed an issue where the internal PubSub notification WebSocket was slow to detect and react to disconnects. This could lead to errors when creating or joining lobbies and matchmaking tickets.
• Fixed an issue where failure of PubSub to establish a connection with the SignalR service wouldn't trigger a failed state change and wouldn't allow subsequent Multiplayer API calls to subscribe to PubSub.

Media

Fixed an issue that caused the title to stop responding because of incorrect fence waits. This occurred during Source Reader shutdown with High Efficiency Video Coding (HEVC) video playback.

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the October 2024 GDK Update 3.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed.

Applies to the following:

• April 2025 GDK
• October 2024 Update 1 GDK and Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

A fix to enable heap dumps to be completely written from Visual Studio will be made in future GDK updates.

GDK tools

In Visual Studio 2019, opening the GDK Help file by using the "?" button from the Xbox Gaming Explorer or any other Xbox tool windows in Visual Studio 2019 causes the GDK Help file to open to its overview page. This occurs rather than the topic page opening that's specific to the tool being used. This issue doesn't occur when using Visual Studio 2022.

Documentation

Offline documentation for the October 2024 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at http://aka.ms/gdkonline.

April 2025 GDK Update 3 v2504.3.4084

April 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the April 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • April 2025 GDK Update 3
  • April 2025 GDK Update 2
  • April 2025 GDK Update 1
  • April 2025 GDK
• Known issues
• Documentation

What's new in the April 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

April 2025 GDK Update 3

Notifications

Networking

The XCurl default receive buffer size has been increased from 8 KB to 16 KB and improves the download speed of large requests. This new buffer size now matches that of LibCurl.

GDK tools

The build ID and content ID are both now available in the output data when running wdapp.exe /list /d and wdapp.exe /listdlc /d on a PC.

April 2025 GDK Update 2

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

April 2025 GDK Update 1

Notifications

GDK tools

Display IDs are now available by running the list-displays command in wdCapture to specify which display to capture.

Media

The XAppCaptureCancelUserRecord API has been added. It allows recordings that were started by XAppCaptureStartUserRecord to be stopped without the recording being saved.

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error was previously displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Fixed an issue in makepkg.exe that will, in the future, allow developers to upload packages with localized display names.

Xbox services

Fixed an issue that could cause high service loads because of Real-Time Activity resyncs.

April 2025 GDK

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the April 2025 GDK Update 1.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Applies to the following:

• April 2025 GDK
• October 2024 GDK Update 1 and October 2024 GDK Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

Documentation

Offline documentation for the April 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.

April 2025 GDK Update 2 v2504.2.4061

April 2025 Microsoft Game Development Kit (GDK) release notes

Introduction

Welcome to the April 2025 Microsoft Game Development Kit release. You can use the GDK to develop games that can be certified and approved for release on Windows 11 PCs and Windows 10 PCs.

About this document

We have organized this document into the following sections.

• What's new
• Release notes:
  • April 2025 GDK Update 2
  • April 2025 GDK Update 1
  • April 2025 GDK
• Known issues
• Documentation

What's new in the April 2025 Microsoft Game Development Kit

• The GDK is released in two types: Major (focused on features, two times a year) and Updates (focused on fixes, as often as needed).
• To view the full What's New section, see the online version of What's New.

April 2025 GDK Update 2

Notifications

GDK tools

The /updatesubval flag has been added to MakePkg for checking for a newer version of SubmissionValidator.dll. If this flag is used and a newer version of SubmissionValidator.dll is available, MakePkg downloads and places the .dll file in the path for MakePkg.

Issue fixes

System

Fixed an issue that affected Unity where XStoreQueryGameLicenseAsync failed and returned the E_INVALIDARG error when the Xbox console language was set to one that used a comma (,) for decimals.

April 2025 GDK Update 1

Notifications

GDK tools

Display IDs are now available by running the list-displays command in wdCapture to specify which display to capture.

Media

The XAppCaptureCancelUserRecord API has been added. It allows recordings that were started by XAppCaptureStartUserRecord to be stopped without the recording being saved.

Issue fixes

GDK tools

Fixed an issue that caused heap dumps to be only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error was previously displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Fixed an issue in makepkg.exe that will, in the future, allow developers to upload packages with localized display names.

Xbox services

Fixed an issue that could cause high service loads because of Real-Time Activity resyncs.

April 2025 GDK

Known issues

Heap dumps aren't written completely

Resolved: This issue is resolved in the April 2025 GDK Update 1.

Heap dumps are only partially written when using Visual Studio or when calling MiniDumpWriteDump from within the title. The following error is displayed.

"Failed with error (0x8007012B): Only part of a ReadProcessMemory or WriteProcessMemory request was completed."

Applies to the following:

• April 2025 GDK
• October 2024 GDK Update 1 and October 2024 GDK Update 2

Workaround

You can use one of the following workarounds:

• When calling MiniDumpWriteDump directly, add the MiniDumpIgnoreInaccessibleMemory flag to the DumpType parameter.
• Heap dumps can also be successfully taken by using the version of xbWatson in either Update 1 of the October 2024 GDK or the April 2025 GDK.

Documentation

Offline documentation for the April 2025 release of the GDKX is installed on your development PC by the GDKX Setup program. After running Setup, the Help file for the GDKX (gdk.chm) is in C:\Program Files (x86)\Microsoft GDK\Documentation.

• The online GDKX documentation is at https://aka.ms/gdkonline.