You did tell me before that the non unicode languages support was being removed from Webmin/Virtualmin, and you suggested to use UTF-8 instead of our working non unicode encoding. I of course followed your advice and set up our new Virtualmin Pro to use UTF-8 US as default before migrating all virtual servers from our old CentOS 5 box using non unicode EN(us). I was afraid that we would run into trouble using UTF and I was right! We had to manually change lots of information, especially use info, and some servers has really lots of users, that took some time to finish but that is all done now.
Now we again run into UTF-8 problems! When adding a automatic reply in "Virtualmin/Edit Users/SELECTED-USER/Mail forwarding settings/Send automatic reply" the reply is crap, no matter what I select in "Automatic reply options/Character set for reply message" the user name in "from" field is crap or the whole message is crap when the sender gets the auto reply. User has Swedish characters in his "Real name" field and that name always is crap in the received auto reply! I also tried to change/re-typed the user real name even though it's OK in the form. This is due to the totally worthless UTF-8 encoding that never works anywhere! We never had any problems with this on our old box set up with non unicode EN. NOTE this is done by me(root) in Virtualmin/Webmin as our customers wants us to administrate these things.
I thinking on switching the language in Webmin/Virtualmin to a working encoding, the non unicode English US(en) but I don't know how long you will keep it. I have been asking before if the non unicode languages really will be removed, and when in that case. Before I do the massive work of updating hundreds of users and all other things to non unicode again i want to know how long you will support it.
We do ran in to these UTF problems all the time, and almost everywhere. If you do a web search of unicode and unicode problems or unicode vs. non unicode you get tons if articles about the UTF problems. But if you live in a country with only the basic US/EN characters your in luck, other wise you are about to get trouble. Almost every article recommends people who are thinking of switching to unicode to stick with non unicode.
I use CentOS 7.4.1708, Webmin 1.881, Usermin 1.741, Virtualmin 6.02 Pro, Authentic Theme 19.12 on our server. My workstation in a Windows 10 Pro Swedish 64-bit, MS Office 365 Swedish (mail client is Outlook), and Latest Firefox Swedish (auto selected my language on install).
Best regards, Leffe