Hi, after some of you are using https://github.com/astares/Seaside-Bootstrap4 I wanted to let you know that I just published the new / updated project to support for Bootstrap 5 web development (https://getbootstrap.com) in Seaside using Pharo.
Project location is on GitHub: https://github.com/astares/Seaside-Bootstrap5 It might not be fully complete by 100% with all new possibilities of BS5 - but it is usable and tests are green in Pharo 8 and Pharo 9. Examples are included, just follow the instructions on the Github page. Feel free to send contributions via PR's. Have fun! T.