Using this terminal command people were able to get App Store apps running on the broken 10.13 version:
sudo sqlite3 /Library/Keychains/crls/valid.sqlite3 'delete from serials where hex(serial) = "04CA81F77D5E33F7”'
However I believe this needs to be applied regularly until Apple has a real fix.
Pleasant surprise! ...
Right now I have downloaded apps that I had bought from the App Store (including BST) and having updated my iMac (mid 2010) to Higs Sierra (V.10.13.6) they have started working as usual.
Apple has fixed it without the user having to do anything! ...
Thanks Andreas and I have already read your contribution in the discussion of the Apple Community forum. 
Cheers