If it could be help designers !
Migration from bootstrap 4 to BT5 :

1 - convert all spacing (margin/padding) with
l (left) to s (start)
r (right) to e (end)

2 - convert text-*
text-left to text-start
text-right to text-end

3 - Dropdown menu
In navbar : data-toggle="dropdown" to data-bs-toggle="dropdown"

4 - Forms
Dropped .input-group-append and .input-group-prepend. You can now just add buttons and .input-group-text as direct children of the input groups.

5 - Carousel
data-ride to data-bs-ride
convert list to button
data-slide-to to data-bs-slide-to
use new class to the previous and next button on control button

6 - Jumbotron
Dropped the jumbotron component as it can be replicated with utilities
See here example without jumbotron

Thank you! This was very helpful!

7 - Badge
Dropped badge-* color classes for background utilities (e.g., use .bg-primary instead of .badge-primary).
badge-pill to rounded-pill

8 - Toast
Check new positions

Core xswatch5 done :
https://github.com/alain01/xswatch5

My "to do list" now :
overloaded templates
- system
- pm
- xmnews
- xmdoc
- xmcontact
- xmcontent
- xmsocial
- profile


For other modules, you should work to migrate

You can submit here : https://github.com/alain01/xswatch5/pulls