microsoft/MIDI inbox-preview-11

In-box Preview 11 (API surface lock)

Repository: microsoft/MIDI

Tag: inbox-preview-11

Published: 2026-10-12T02:42:08Z

Prerelease: yes

Release notes:

In-box Preview 11

This is open to all customers who would like to try out the features and functionality. Installing these components will not break your existing Windows MIDI Services OS-delivered components install.

Key items

• New app: Windows MIDI Sequencer. Arrange, record and play MIDI 2.0 music on a timeline, with a clip launcher for playing live. It's a very early preview.
• Windows MIDI Patchbay was rebuilt. A library of your patches, a window for each patch, and new steps for logic, MIDI-CI, MIDI clock, MIDI Time Code and LFOs.
• Windows MIDI Glass layouts and themes can be shared as packs, signed by their publisher, and say who made them.
• The Windows MIDI Services API is locked. The only addition since Preview 10 is MidiApi.IsSystemProvided().
• Network MIDI Setup can let the MIDI service through Windows Firewall for you.

Packages and Installation Instructions

If you are running any of the older rc4 or similar SDK Runtime and Tools, or any of the older preview transports, fully uninstall them from Settings > Apps > Installed Apps before installing anything here.

Install the Tools package to have access to all the in-box tools required to configure endpoints, customize, route MIDI endpoints, create controller surfaces, and much more. Everyone will want this package. The tools are documented on the tools page.

Install the Transports package to have access to preview versions of

• General MIDI Synth
• Basic MIDI 1.0 Loopback Transport
• RTP-MIDI Transport
• Network MIDI 2.0 Transport
• Bluetooth LE MIDI Transport

You can turn the individual transports on or off on the Transports page of MIDI Troubleshooting and Repair, which is in the Tools package.

If you installed the separate Preview 9 or Preview 10 transport installers, you don't need to remove them first. The Transports package removes them when it installs. Uninstalling them first won't cause any harm. The uninstall instructions above are to cover everyone, regardless of what they have installed. When in doubt, uninstall the old stuff.

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Details for Developers and Technical Customers

The metadata for the Windows.Devices.Midi2 API is now locked, and breaking changes are no longer permitted.

Developer permitted use

We want to ensure customers have the best experience going forward. Because of this, we want to ensure that these app-local binaries are not normally present on customer systems which have the binaries in System32.

Distributing these API binaries is a choice you make. Although we will try to keep compatibility, Microsoft makes no guarantee that the in-box API binaries or service transports will be compatible with this Preview release. If that is not acceptable, please wait to distribute your app until the transports and API ship in Windows.

Developer Go-live agreement

This is the second Windows MIDI Services API release with a "go live" license for Windows.Devices.Midi2.dll, .winmd, and .pri and it carries the same agreement as Preview 10.

This is still a preview, and we want to ensure that customers have a great experience going forward, so if you do go live with this, you need to agree to the following:

By distributing the API binaries with my app, I (the developer of the app) agree:

1. I have a mechanism to update the app to remove the API binaries once they are in-box in Windows, and to keep up to date with any additional previews. 2. I will make all possible efforts to keep up with any additional preview releases, and update my app to include those, ensuring customers have the latest fixes and features at least up through the point where we announce that the API surface area / metadata is locked 3. I will let my customers know that I am using preview Windows MIDI Services APIs, until the point when the preview API is removed from my product. 4. I will not ship the Windows.Devices.Midi2 API to versions of Windows below Windows 11 25h2 (Windows 11 24h2 is unsupported, and will not get the required fixes, so we recommend customers move to a supported version of Windows 11, or switch to Legacy API Mode) 5. I will file bugs on GitHub for any issues I encounter, and make an effort to assist in the debugging of the reported problems. 6. When the 1.0 version of the Windows MIDI Services WinRT API is in Windows, and I have a new release of the app built against it, I will make an effort to contact my customers to inform them of the new version and encourage them to update to it, if that process is not automatic.

Failed WinRT component activation is typically projected as an exception in your applications, so keeping up to date with the latest updates is important. Microsoft will endeavor to lock the API well before the expected release date so this isn't a last-minute surprise, but there's always the possibility that the .winmd has to differ in some way in the in-box version.

Note: The .pri file contains resources and must be installed with the dll. In the distribution acquired here, the resources are en-US only. The version that ships in Windows will be translated.

Remainder

This set of release notes only covers the delta from Preview 10. Please refer to Preview 10 and earlier for everything before that.

Installers

Each platform still has two installers, Tools and Transports, the same as in Preview 10.

• Windows MIDI Services Tools (0.99.92-preview.11) adds the new Windows MIDI Sequencer. Its shortcut, MIDI Sequencer, is in the Windows MIDI (Preview) folder on the Start menu with the other apps.
• Double-click a .midisequence file to open it in Windows MIDI Sequencer. It's also offered under Open with for .mid, .midi and .midi2 files, and imports them into a new sequence.
• File Explorer now calls .midilayout and .midipatch files Windows MIDI Glass layout and Windows MIDI Patchbay patch.
• Windows MIDI Services Transports (1.0.41-preview.9) has the same five transports as Preview 10.

API Changes

NuGet package version for this release is 0.99.92-preview.11.

As noted above, this release locks the interfaces and their contracts. Since Preview 10, the API gained one...