Remember when Nokia’s TV ads for its Lumia 900 mocked other smartphone vendors for treating their users as beta testers? Those ads look a little cruel after Microsoft revealed that no current WP7 device will get an update to its upcoming Windows Phone 8, which has new features like turn-by-turn navigation and Internet calling.

Instead, the 900 — priced at $99.99 and available exclusively on AT&T’s network in the United States — won’t advance past a “Windows Phone 7.5 refresh” patch and a later WP 7.8 update adding WP8′s more customizable start screen.

But the current software itself doesn’t feel old, aside from its embarrassing reliance on desktop programs to sync files and install even minor updates. This operating system’s basic innovation — making the start screen a stack of easily rearranged, interactive tiles that present notifications from your apps — remains an intelligent, fast way to stay on top of your life.

The hope that the Lumia would reboot the entire Windows Phone market hasn’t panned out, though. WP7′s 1.3% share of the smartphone installed base remains smaller than that of the unlovable Windows Mobile software it replaced, according to Nielsen’s figures.