New in Flow 6.3:
- Performance optimisations, most notably when matching CSS.
- Added structuredClone() and reportError().
- Improved stack traces when exceptions thrown.
- about:blank same-origin fixes.

New in Flow 6.2:
- Improvements to the JS API, beginning the update towards SVG 2 and making it easier to support shadow nodes
- Asynchronous scrolling bug fixes
- Work on CSS includes adding pseudo :where(), updating :not() to CSS4
- Reintroducing SVGMatrix for web compatibility

New in Flow 6.1:
- Scrolling is now handled on a different thread to the browser layout and JavaScript. Still incomplete, this lets you scroll whilst the rest of the browser is busy
- Optimisations for YouTube's home page
- Optimisations after profiling loading large HTML pages