Emails created with eM Client 7 have XML format instead of HTML. Can this be changed?

Hello everyone,

Upgraded to version 7 and faced the following issue.

eM Client 6 generates the following header for HTML part of the message (which I believe is correct):

Content-Type: text/html; charset="utf-8"

In eM Client 7 email format has changed to XML for some reason:

Content-Type: text/html; charset="utf-8"<?xml version="1.0" encoding="utf-16"?>

Content type and document type now do not match each other.
Some email clients show messages like that incorrectly.

Is there a fix or a workaround to bring them in sync in version 7?
Thanks in advance for any hint!

Regards,
Nickolay

I wonder if anyone else faced this issue too or it’s only me so unlucky…