Load text messages on new phone My personal phone is iPhone 5.

Boss bought me a new company phone, iPhone 7.  And it syncs with Microsoft Exchange server for email, etc.  Before I got this new phone, I used my old one for work, especially texting.

How can I get the old text messages (and only the text messages) from the 5 onto the new 7?  I do not want to backup/restore because I need to keep the configuration and current settings of the 7.
I think easiest way would be to load a backup on your new phone, but you said that is not possible. 
In this article 3rd party software ist used.
http://www.macworld.co.uk/how-to/iphone/how-to-transfer-text-messages-from-one-iphone-another-3525410/