Cyrillic letters ignored

As far as I know, the root of the problem is actually with some PDF viewers not rendering forms properly.

I have already begun work on replacing the back end filling functionality using a different tool set which seems to have a solution for this issue. Unfortunately, it is slow going, mostly due to me being busy with other priorities. I don’t have an ETA for you at the moment.

The only workaround I am aware of is to re-save the file using either Adobe Acrobat or Foxit Reader. This doesn’t solve all of the issues, however, I think it would work with Cyrillic.

Thanks for your reply!
However, I don’t think it has to do with the viewer, I’m opening the created file with Adobe Acrobat and all the fields I filled with cyrilic letters are simply blank. Resaving the file does not solve the problem..

Can you send me the filled PDF file to admin at maximum dot software? I would like to see what the problem is exactly. Sometimes an issue can be related to fonts.

Sure, I’ve just sent it.

Looks like you are using the flatten option. If you can, try disabling the flatten option. Unfortunately, there is no work around with the flatten option enabled. I will see if I can expedite the development of the new version of the backend.

Yes, you are right. At first I was using it without flattening option, but pdf did not look right, because the fields were outlined and grey, indicating that viewer can change them, so I have decided to flatten it.
I tried again, without flattening, and the letters show just fine, and the solution to avoid highlighting was to mark the field as Read only in my pdf.
So, I can confirm this works well now!

Many thanks for your hint, wish you very well 2020!