- [#3811](https://github.com/less/less.js/pull/3811) add support for [container queries](https://www.w3.org/TR/css-contain-3) (@puckowski)
- [#3761](https://github.com/less/less.js/pull/3761) fix faulty source map generation with variables in selectors, fixes [#3567](https://github.com/less/less.js/issues/3567) (@pgoldberg)
- [#3700](https://github.com/less/less.js/pull/3700) parsing variables fail when there is no trailing semicolon (@b-kelly)
- [#3719](https://github.com/less/less.js/pull/3719) modify `this` pointer so that it is not empty. (@lumburr)
- [#3649](https://github.com/less/less.js/pull/3649) fixes [#2991](https://github.com/less/less.js/issues/2991) empty @media queries generated when compiling less file with (reference) to bootstrap (@MoonCoral)
- [#3602](https://github.com/less/less.js/pull/3602) Fix currentFileInfo and index properties on nodes (#3602) (@bjpbakker)
- [#3626](https://github.com/less/less.js/pull/3626) Fix [#3616](https://github.com/less/less.js/issues/3616) IfStatement requires double parentheses when dividing (#3626) (@iChenLei)
- [#3630](https://github.com/less/less.js/pull/3630) Fix needle dependency warning typo. (#3630) (@cjwilsontech)
- [#3597](https://github.com/less/less.js/pull/3597) Fix expected response when there's a socket error (#3597) (@zxfrank)
- [#3589](https://github.com/less/less.js/pull/3589) Fixes [#3586](https://github.com/less/less.js/issues/3586) (#3589) (@matthew-dean)
- [#3582](https://github.com/less/less.js/pull/3582) Fix [#3576](https://github.com/less/less.js/issues/3576) import redirects. Replace native-request with needle. (#3582) (@zaquest)
- [#3583](https://github.com/less/less.js/pull/3583) Update rollup and other build dependencies (#3583) (@pravi)
- [#3588](https://github.com/less/less.js/pull/3588) Roll back paren requirement on mixin calls (#3588) (@matthew-dean)
- [#3573](https://github.com/less/less.js/pull/3573) v4.0.0 (#3573) (@matthew-dean)