Some amendments in the code to make plugin compatible with WPML, were made in May, 2019. Recently, plugin got official status of compatibility to WPML.
WPML has internal procedure of testing themes and plugins to confirm their compatibility. Product passes thorough check by developers from Compatibility Team. Upon confirmation of compatibility, company issues a certificate (attached to this post), and makes publication on own site.
During a month, on WPML site will be published a digest of new plugins and themes, which received compatibility status. It will include Cyr-To-Lat.