Acknowledgement from HTC north american support tech
I'm copying the last response I received from HTC:
Thank you for your reply regarding synchronization of your HTC Desire HD device from TELUS with your Microsoft Exchange account.
I know the importance of synchronizing your phone with your Exchange account. I have forwarded your email to the appropriate department.
Our Mail application is generally updated when we release a software update, so the application may no longer be fully compatible with your Exchange account
It appears that your device may be experiencing a compatibility issue with Exchange 2010 following the update. I recommend you continue using the “Touchdown” application for email pending a solution to the issue.
Please include in your response the Outlook Web Access (OWA) number for your Exchange server. Please also include the following information:
Your mobile phone number and an alternate contact number, if available.
Your time zone and a period of time you would prefer a representative to contact you if necessary.
The location where this issue occurs, i.e., street address, city, and province.
On receipt of your response, I will forward your inquiry to our Escalation Department.
We apologize for any inconvenience you may have experienced.