android email client Microsoft exchange connection

We have a mail client that was build on top of K-9 android email client with changes for our specific needs. What we lack and we need is that this mail client also works with Microsoft exchange and Office365 connections (active sync) to receive, send, delete, move emails. The client supports POP/IMAP/SMTP, but we changed to exchange emails for security reasons. The client also supports WEBDAV which we do not need. Current up-to-date version of K-9 mail client does not support exchange (active sync) and this has to be incorporated to the current version of K-9 to successfully sync (send, receive, delete, move) emails with the exchange (active sync) servers. You will find attached an image where this option in the image should be added to the existing K9 accounts page. We do not need it to look the same or any icon, just the functionality as mentioned above.