Announcing Tornado version 6.5.4

[Ben Darnell]

Tornado version 6.5.4 is now available. This fixes a regression in last week's release 6.5.3.

https://www.tornadoweb.org/en/stable/releases/v6.5.4.html

What’s new in Tornado 6.5.4¶

Dec 15, 2025¶

Bug fixes¶

• The in operator for HTTPHeaders was incorrectly case-sensitive, causing lookups to fail for headers with different casing than the original header name. This was a regression in version 6.5.3 and has been fixed to restore the intended case-insensitive behavior from version 6.5.2 and earlier.