It is necessary to enable developer mode to run userscripts via Tampermonkey now.
Instructions on how to enable it can be found
here.
Microsoft Edge
General
Added a setting to control whether GM_cookie should be able to access HttpOnly cookies
Added button to force update externals
Fixed header-derived filenames in GM_download
Reworked counting of executed script instances
Enhanced back/forward cache navigation handling
Fixed an GM_registerMenuCommand issue with non-letter accessKeys
Added a warning message when a script without @include and @match entry is saved the first time
Fixed storage change listeners after clicking a download link
Fixed issues with GM_registerMenuCommand if the command was registered multiple times (e.g. from different frames)
UI
Added a button to disable script updates at the update dialog
Improved editor search functionality
Fixed code selection near the top and bottom of the editor
Fixed editor height issue in mobile views
Show an error icon at scripts without any @include and @match entry
Sync
Fixed synchronization issues with WebDAV
MV3
Manifest v3 requires a different workflow when installing a userscript
Note: you can restore the old behavior, by changing Userscript URL detection to Legacy
Locales
Updated Portuguese-Brazil translation | thanks to igorruckert
Updated Italian translation | thanks to bovirus
Updated Japanese translation | thanks to shirayuki
Known Issues
GM_webRequest is not (yet) supported in Manifest V3
GM_xmlhttpRequests fires only one progress event (you can use responseType stream for now)
In UserScript API Dynamic mode scripts that are using a RegExp @require cause overhead by being injected into every frame
GM_xmlhttpRequests are running serialized workaround available