Here are some major point
1 Bootstrap no longer depends on jQuery
2. Dropped support for Internet Explorer (up to IE-11)
3. Updated forms element
4. Added one more breakpoint
$grid-breakpoints: (
xs: 0,
sm: 576px,
md: 768px,
lg: 992px,
xl: 1200px,
xxl: 1400px
);
5. Added RTL Support
6. added Theme colors support in SASS
7. Gutters
Gutters are the padding between your columns, used to responsively space and align content in the Bootstrap grid system.
8. Responsive font sizes
Enabled responsive font sizes by default, allowing the text to scale more naturally across device and viewport sizes. Have a look at the RFS page to find out how this works.
9. Stretched link
10. Gap
When using display: grid, you can make use of gap utilities on the parent grid container. This can save on having to add margin utilities to individual grid items (children of a display: grid container). Gap utilities are responsive by default, and are generated via our utilities API, based on the $spacers Sass map.
11. Components
- Renamed
.dropleftand.droprightto.dropstartanddropend. - Renamed
.dropdown-menu-*-leftand.dropdown-menu-*-rightto.dropdown-menu-*-startand.dropdown-menu-*-end. - Renamed
.bs-popover-leftand.bs-popover-rightto.bs-popover-startand.bs-popover-end. - Renamed
.bs-tooltip-leftand.bs-tooltip-rightto.bs-tooltip-startand.bs-tooltip-end. - Renamed
.carousel-item-leftand.carousel-item-rightto.carousel-item-startand.carousel-item-end.
12. Utilities
- Renamed
.left-*and.right-*to.start-*and.end-*. - Renamed
.float-leftand.float-rightto.float-startand.float-end. - Renamed
.border-leftand.border-rightto.border-startand.border-end. - Renamed
.rounded-leftand.rounded-rightto.rounded-startand.rounded-end. - Renamed
.ml-*and.mr-*to.ms-*and.me-*. - Renamed
.pl-*and.pr-*to.ps-*and.pe-*. - Renamed
.text-leftand.text-rightto.text-startand.text-end.
Breakpoints specific variants are consequently renamed too (eg. .text-md-start replaces .text-md-left).



