Just two months after Windows Phone 7.5 began rolling out to devices, the update is complete. Starting today, the Dell Venue Pro is getting its Mango on AT&T. That marks the last original Windows Phone 7 handset to receive the latest version of Microsoft's mobile operating system, with all the delectable additions it brings — Telefonica's Omnia 7, the other straggler, began receiving the update last week. Android users might envy the relative speed and ubiquity of the Windows Phone 7.5 update process, particularly if they had an early handset, but it's not completely surprising given how closely Microsoft dictated the specs of WP7 devices to begin with.