How to upgrade windows mobile 6.1 to windows mobile 6.5?

As Microsoft has already made Windows Mobile 6.5 official, most of the current mobile users with WinMo 6.1 are eager to know if they can upgrade their devices to Windows Mobile 6.5 or not. Unfortunately upgrade of 6.1 to 6.5 is more significant and complex than 6.0 to 6.1 and involves a lot of optimization.

There is this article which gives some hope to users with HTC phone eager to upgrade.