How to open/read an hbk file of saved texts when i no longer have an htc phone.

[AC Question]

I used to have an HTC one m8 phone. I had decided to go with a different phone. Before purchasing my new phone (Asus zenphone2) the AT&T rep. saved all my texts and sent them to me in an email and it saved this file as an hbk file. I now have this new phone with the hbk file on it and cannot figure out how or if it's even possible to open and read this file. Any advice/help?