According to Gizmodo, they recently received a tip informing them that the T-Mobile Dash will be upgradeable to Windows Mobile 6. The update will be released in the spring of this year.

This is great news for me, I recently accepted a new position with another company and they use T-Mobile, so I'll be switching from Verizon and my i730 to T-Mobile. The i730 has been giving me problems constantly, it will be great having a new Windows Mobile device and a Dash.