I sent the following email to tmobile the other day.
And i got the following reply
Thanks for your email about when we'll be updating MDA Vario software to version 6.
I'm pleased you've emailed me about this, I can appreciate how important it is to know what software is available for your mobile.
I'm happy to tell you that we're anticipating the launch of Windows mobile version 6 in September this year.
I hope you find this information helpful, if you need any further assistance feel free to either reply to my email or contact our customer service team on 150 or on 0845 412 5000 from a landline.
Thanks again Dave for taking the time to email me.