We are using free version 4.7, build 5776 as smtp proxy.

Office365 users can't send to us mail. The error is returned '450 4.4.317 Cannot connect to remote server [Message=451 5.7.3 STARTTLS is required to send mail

When I ehlo xeams, there is no "250 STARTTLS". 

Starttls in smtp proxy is available from version 4.7.

Does it mean that free version won't receive mails from office365 users?

Or I just missed some configuration?