What's changed

• Replace Sass division with multiplication and custom divide() function by @mdo in https://github.com/twbs/bootstrap/pull/34571
• Update RFS to v8.1.0 by @XhmikosR in https://github.com/twbs/bootstrap/pull/34571
• fix(forms): input-group and validation icons by @ffoodd in https://github.com/twbs/bootstrap/pull/32968
• Fix minor visual bug in Firefox caused by moz-focusring by @kremit in https://github.com/twbs/bootstrap/pull/32821
• Adjust SAFE_URL_PATTERN regex for use with test method of regexes by @nikonthethird in https://github.com/twbs/bootstrap/pull/33153
• Add sms in the SAFE_URL_PATTERN for sanitizer by @XhmikosR in https://github.com/twbs/bootstrap/pull/35074
• Adjust feedback icon position and padding for select.form-control by @mdo in https://github.com/twbs/bootstrap/pull/33206
• Carousel: use buttons, not links, for prev/next controls by @patrickhlauke in https://github.com/twbs/bootstrap/pull/33165
• v4: Sass docs for default variables by @mdo in https://github.com/twbs/bootstrap/pull/33392
• Handle complex expressions in add() & subtract() by @ffoodd in https://github.com/twbs/bootstrap/pull/34047
• More concise improvements for add() and subtract() by @ffoodd in https://github.com/twbs/bootstrap/pull/34432
• Remove aria-haspopup from dropdowns by @patrickhlauke in https://github.com/twbs/bootstrap/pull/33624
• Dropdown: support .dropdown-item wrapped in <li> tags by @cpsievert in https://github.com/twbs/bootstrap/pull/33649
• Update Node versions in JS tests (drop Node 10, add Node 16), update docs JS assets and add variables for vertical-align in spinners by @XhmikosR in https://github.com/twbs/bootstrap/pull/33807
• Replace Freenode with Libera IRC server by @midzer https://github.com/twbs/bootstrap/pull/34050
• Fix repetition in the Navbar docs description by @coliff in https://github.com/twbs/bootstrap/pull/34208
• Enable 0.x with negative margins in utilities by @k-utsumi in https://github.com/twbs/bootstrap/pull/33593
• Remove print thead rule by @coliff in https://github.com/twbs/bootstrap/pull/34426
• Fix prevented show event disabling modals with fade class from being displayed again by @alpadev in https://github.com/twbs/bootstrap/pull/34087
• Input group validation with custom-file input by @ffoodd in https://github.com/twbs/bootstrap/pull/33239
• Add eslint-plugin-qunit and tighten JS tests by @XhmikosR in https://github.com/twbs/bootstrap/pull/32270
• Update our tests to Node 16 and npm 8 by @XhmikosR in https://github.com/twbs/bootstrap/pull/35142
• Disabled link cleanup by @patrickhlauke in https://github.com/twbs/bootstrap/pull/34924
• Updated our devDependencies including terser; also enabled two passes for terser by @XhmikosR

Full changelog

https://github.com/twbs/bootstrap/compare/v4.6.0...v4.6.1