v2026.9.18.0 svelte@5.57.1
qdm12/dnsSep 18, 2026 → Sep 18, 20260 days between releases
What's New
Fixes SSR event listener cleanup and CSS preservation issues in Svelte 5.57.1
Breaking Changes
- Throws error if setContext is called after an await during SSR
- Removes WAS_MARKED flag in favor of Set
New Features
- SSR garbage collection reduction
- Parser performance improvements
- Reactive state fixes
Improvements
- Speed up parser interactions with Acorn
- Avoid regex matching in parser where possible
Bug Fixes
- Cancel deferred event listeners during cleanup
- Preserve global CSS in components without scopable elements
- Reduce SSR render result garbage collection
- Serialize input default values during SSR
- Make Object.hasOwn reactive for state proxy ownership changes
Upgrade Notes
Ensure code does not call setContext after an await during server-side rendering to avoid errors. Check CSS scoping behavior in components without scopable elements.
The Two Releases
v2026.9.18.0
Sep 18, 2026· 1 month ago
This release introduces a new navigation stack primitive, updates the agents view with Claude Cloud support and GitHub PR status chips, and fixes various responsive UI issues across the application.
Full release notessvelte@5.57.1
Sep 18, 2026· 1 month ago
A patch release addressing SSR issues, event listener cleanup, and CSS preservation. Includes performance optimizations in the parser and fixes for reactive state and component rendering.
Full release notes