On February 1st HTC released a hotfix to correct the problem of texts appearing to come from 2016:
http://www.htc.com/us/support/mogul-sprint/downloads/
Attached is the official cab from htc, if it wont install on your device i have also attached the rillphone.dll extracted from that cab for you to copy directly to your device. In order to do this you first need to put the phone in airplane mode and extract the rillphone.dll file to the windows directory of your phone and overwrite the old one.
Also attached is a program extracted from the cab correcttimestamp.exe that you can run on your phone that will fix the time stamp on all your old texts.