Thanks for the solution for the dog-slow HTC Messaging App.
I installed it on Miri 7.1 and have only one issue with. When you open a person from contact list or favorites and press "Send Message" nothing happens. Pressing "Send Email" opens Outlook to send an e-mail, but "Send Message" does not open Outlook SMS editor.
interesting, I have no problem. Pressing 'Send Message' in the contact's home tab brings me to the contact's text messaging tab.