The page announces the htmx 4.0.0 release, documenting major changes including explicit attribute inheritance, standardized event naming conventions, reworked history handling, and a migration from XMLHttpRequest to fetch(). It also introduces new features such as built-in morph swaps, the hx-partial tag, and a refreshed extension ecosystem.
This resource is most valuable when upgrading an existing htmx 2.x application to 4.x, debugging event name or history behavior changes after an upgrade, or deciding which htmx version line to adopt for a new project. Note that 4.0 is published under the 'next' NPM tag rather than 'latest' until early 2027.