After update, old bootstrap 3.3.7 is still being loaded (18.104.22.168-RC3 have bootstrap 3.4.1) in admin and login ui page.
This is fixed by changing bootstrap version in ui-themeconfig.json. I didn't found any note in documentation about update of themeconfig file. If update process cannot handle update of ui-themeconfig.json, we should at least document need of manual change.
Affected updates from