Is Bootstrap 4 officially supported for KendoUI for jQuery?
Technically speaking, those are two separate and independent frameworks and there isn't any cross-framework support. That being said, we've ensure compatibility with Bootstrap 4 in terms of appearance. More specifically, we have a sass-based theme called Bootstrap-v4 that reuses the variables used in Bootstrap 4 (which is also based on sass). In other words if you have a custom variable file that can customize Bootstrap, it will also customize Bootstrap-v4 theme, to an extent that is.
How to include Bootstrap v4 theme / How to upgrade to Bootstrap 4?
* To include Bootstrap-v4 theme, you need only a single file (that's an advantage over less-based themes, which needed two files) -- kendo.bootstrap-v4.css or kendo.bootstrap-4v.min.css
* To use Bootstrap 4 you need to include it like you would.
I've created a very simple dojo -- https://dojo.telerik.com/@joneff/AjeBeXAH
-- that shows Bootstrap buttons and textboxes, as well as KendoUI Bootstrap v4 theme counterparts. The only difference is in the shade of default (secondary) buttons. We've opted for a lighter shade of gray.