Made a GitHub repository for converting the oscommerce's admin to bootstrap 4. based on @burt 's oscommerce-CE [Frozen] repository BS4 Admin (<- click to download)
TODO:
use direct library instead of CDN
Finetune buttons.
Remove obsolete html.
replace images with icons.
Re-positioning of several buttons, search-fields and drop-downs. perhaps this list will go be extended
Have Fun!