I use beta276 and Kelopatra and GPA seem to work fine. I don’t install GpgOl, since I don’t use Outlook at all. But, I can’t get GpgEx to work.
The menu is there, but when I tell it to do anything I get an error message.
Oooook, now I learnt something! gpgEx is reliant on Kleopatra running! Didn’t know that. 
Ok, so now I could use it to Decrypt from menu.
For some reason Create checksum doesn’t work.
I get something that looks like a permission error. Because I can’t find such a file anywhere on my computer.
If I create an .md5 file with Total Commander, I can use GpgEx to verify it. I just can’t create one.
If I access the checksum binaries in C:\Program Files (x86)\Gpg4win\bin> I can use them to both check files and create checksums. (md5, sha1 & sha256).
But if I use the right-click menu creating checksums doesn’t work.
Urgh. Right. This did not work at all after our migration in Kleopatra to Qt5. Then I fixed it but only tested it on Linux (where the overwrite works because linux filesystem allows to overwrite opened files) on Windows though it does not.
Thanks for reporting. Will be fixed.
So the overwriting of sha256sum.txt and sha1sum.txt files are intentional? Why not have the checksums be added to them rather then replace them?
I’ve been wondering why my saved sums kept disappearing before I figured that out.
I’d prefer if the checksums had the name of the accompanying file with .sha1 extention, , but I guess there is something in the specifications that forbids that.
Although veracrypt does offer .filebname_bundle.checksums named files, but they just give an error.
Adding to the file would be complicated internally as we would have to parse it in kleopatra and then basically merge the old and the new file. I don’t like that.
But using the filename + checksum extension I like. We could then also register kleopatra to handle extensions like .sha1 .md5 etc. and Kleopatra would immediately check the corresponding file.
I’ve opened a wish in our development tracker for this: https://dev.gnupg.org/T3800