First of, I would like to applaud the developers for a great tool.
We've been using it for quite some time. But It's frustrating that you constantly need to apply patches found in the forum if you intend to use the system anywhere where you expect non-english tickets.
The main issue is that OsTicket is build around the assumption that everyone speaks english. So one of our main problems is handling incoming mail that contain characters like å, ä, ö, ü, ë, ï etc. in either the senders name, subject or message body. Or even in the names of attached files. By default a somewhat strange DB-Error #1366 is generated every time such a mail is received. I've found a patch for that ((see this post)).
We've still got problems with attachments however. If a mail is received, containing a valid attachment but with characters mentioned above. The attachment is simply stripped from the ticket. No error message, nothing in the PHP logs. It simply vanishes. Is there any known workaround/patch for this? Might be good to know that we use the cron-job instead of autocron if that makes any difference. Secondly, when a staff member attaches a file to a reply, and the attached file contains for example 'å', the mail is sent without any attachments to the customer. But the attachment is attached to the ticket (so the staff member doesn't notice anything wrong). However the attached file will be renamed ('å' is replaced with 'ao'). I would like to see patch for this too, i.e. a patch that doesnt rename the file and actually attaches it to the response when its sent.