Firefox's QUIC stack is moving to a Rust based UDP I/O stack that leverages
Version 140.0.4, first offered to Release channel users on July 8, 2025
New:
- Firefox's QUIC stack is moving to a Rust based UDP I/O stack that leverages various modern, operating system specific calls, resulting in improved HTTP/3 upload and download performance.
Fixed:
- Fixed incorrect font selection in some cases when attempting to use color fonts. (Bug 1971053)
- Fixed the search results not updating when switching source during a file search in the Developer Tool's debugger. (Bug 1971094)