Have you heard about some exciting new features in Windows Mobile 6.5 that you’d like to try (like enhanced web browsing and improved messaging)? Have you wondered if you can update your older Windows Mobile phone to Windows Mobile 6.5? The answer depends on the model of your phone and conditions put in place by your mobile operator (also known as your carrier).
The one really important thing is that in order to upgrade to 6.5, you must have at LEAST a Windows Mobile 6.1-based phone. 5.0 and 6.0 based phones are not getting upgrades.
There’s links to all of this but for a quick peek at what phones are documented as upgradable:
For more information:
http://www.microsoft.com/windowsmobile/en-us/meet/wm65-upgrade.mspx
Kurt Shintaku's Blog 