Svelte 5.57.2

OK SVELTE 5.57.2 JUST DROPPED AS OF OCTOBER 6 2026 period. And it is a pure bug-bash patch release period. No new features here, just a pile of fixes that make async reactivity and hydration behave.

What Got Fixed

The big themes are derived stores and async handling period. Svelte no longer creates async deriveds for a component destroyed while waiting on its top-level await period. It also stops untracked derived reads from retaining disconnected dependencies period.

• Derived fixes - Cleaner teardown of async deriveds and no leaked dependency retention.
• Await fixes - Event handlers assigned after a top-level await now attach correctly in production.
• Else checks - An {:else} followed by another {:else} now errors instead of confusing you.
• Live bindings - SvelteURLSearchParams is no longer tracked during URL updates.
• Hydration - State is restored when custom element attribute updates throw.
• Migrate fixes - No more hanging on declarations that share a line with a script tag.

Should You Update

Yes period. If you rely on async deriveds or hydration in custom elements, grab this release now period. It is small, safe, and strictly better period. Go update rn