Currently, the software works with Windows 8, Windows 7, Windows Vista, Windows XP. There is no information about a possible Windows 10 release. This will take time, since Windows 10 has not been released yet. The official release is on July 29. It's impossible to say if Tildes Birojs will support Windows 10 or not.
Use the contact option on the official website to get in touch with the developer. He should provide all the necessary info about the software.
Contact page: http://tilde.com/about-tilde/contacts