After the "latest" update one of our clients asked us to figure out the issue and it turns out it is related to the mail settings.
Basically all e-mails were being sent with blank text/no body.
The solution
Go to "Setup ->General Settings ->Mail" and just click on "Save" and it will work again.
Note that this assumes you didn't break things yourself by changing any settings. WHMCS may tell y........
After an upgrade wine wouldn't open anything, not even the pre-installed notepad.
There are no wine logs and nothing is mentioned in any standard log file about why.
I finally decided to run wine from the shell and see what's going on:
wine client error:0: version mismatch 398/402.
Your wineserver binary was not upgraded correctly,
or you have an older one somewhere in your PATH.
Or maybe the wrong wineserver is still running?........