Update 1.26 brings Steam Workshop support for custom tracks!
Trombone Champ has been updated to 1.26! This update mainly adds support for custom tracks via Steam Workshop.
Mod compatibility with 1.26
As usual, we've had this update available as a beta for a few weeks so that the community can get a head start on updating their tools. But if you rely on mods that are broken by this update, you can load the previous version of the game by right-clicking the game in Steam, going to Properties, choosing Betas, and then choosing the "last_update" beta branch. But please hop on the newest version as soon as you can!
Browse and subscribe to tracks in Steam Workshop!
You can now browse and subscribe to custom tracks via Steam Workshop! For Steam users, this is probably the easiest way to get started with custom maps. You can view the workshop page here:
https://steamcommunity.com/workshop/browse/?appid=1059990
After subscribing to items, they should appear in a new "Steam Workshop" collection in the "Track Select" screen. You may need to restart the game, or click the "reload" button in the Custom Tracks section of Settings, to make newly-subscribed tracks show up. 
We've personally made two tracks to celebrate the launch of the Workshop, with more to come soon. Vogons is a really fun Max Tundra track, and Item Shopping is a remix of a track from one of our old albums!
https://steamcommunity.com/sharedfiles/filedetails/?id=3480593643
https://steamcommunity.com/sharedfiles/filedetails/?id=3480589806
The community has already uploaded a bunch of tracks to the game's Workshop... and now that the Workshop is public, we anticipate lots of new content soon!
Are you musically inclined?... if so, why not contribute yourself?...
Upload your tracks to Steam Workshop!
We've written a guide on how to upload your incredible tracks to Steam Workshop here:
https://steamcommunity.com/sharedfiles/filedetails/?id=3484303312
To summarize, there's a new button in the Tootmaker level editor:
https://images.steamusercontent.com/ugc/10843595434281437303/E4133A4B332387A02F76E63227A142385603A0FB/
... and when you click the button, you get a popup that should be self-explanatory. All you really need to do is point to a folder, attach a thumbnail image, and click "submit!"
https://images.steamusercontent.com/ugc/13198470362750566460/6173E52813F88D8EAAB416DADF57693302E05CE3/
We plan to hold some sort Workshop contest soon, so if you're interested, check it out!
Other types of content in Workshop?
At the moment, you can only upload custom tracks to Steam Workshop. However, we plan to continue experimenting with additional workshop functionality. For example, it would be great if users could upload and download gameplay mods in the workshop! However, this will be a bit trickier to implement since it will involve a lot more tracking and file management than custom tracks do.
What's Next for Trombone Champ in 2025
We've been pretty busy over here... in addition to Trombone Champ stuff, we've started prototyping our Next Game (unannounced). Gotta make sure it's actually fun to play before diving in! But, in terms of Trombone Champ, here's what we plan to do next:
We need to update the Nintendo Switch version of the game to address a few (very minor, visual only) issues with the Switch 2 version. It works great, but a few animations run too quickly!
For PC / Mac, we've started going through a bunch of screens and making them look better in ultrawidescreen resolutions. People have been complaining about this forever and it will be nice to get it done!
We'd like to revisit input. We'd love to have nice controller support, mainly so we can get the game working as smoothly as possible on the Steam Deck. Trombone Champ does work on the Steam Deck, but it doesn't control nearly as nicely as it could. (The game was released at a time when the Steam Deck was heavily backordered — we weren't able to get one until much later!)
We're working on some cool secret stuff that we can't share yet! At the moment, we're not even sure how much of this stuff will pan out!
After that, we're probably done in terms of significant updates, but we'll still continue to support the game, fix bugs, and add new tracks.
Thank you for your continued support!!
Forever in your service,
Holy Wow Studios