GoKawiilhtmx 4.0.0 ships with fetch()-based core and explicit attribute inheritance
The htmx team released version 4.0.0 after eight months of development, rewriting the library's internals to use the fetch() API instead of XMLHttpRequest. Key user-facing changes include making attribute inheritance explicit by default, standardizing event names, and dropping localStorage as the default for history support. The team is not marking 4.0 as 'latest' on NPM, keeping 2.x as the default for CDN users until early 2027 while 4.0 becomes the 'next' line.