I'm seeing a 'feature' when updating from build 27 to build 31.
Initially the 'update available' link shows; I click it and get an update to build 30 and the update link goes away. Then, some time later, I see 'update available' again, and this time when I click it I get an update to vtop.php and the build number goes to 31.
Probably not a problem, but a bit odd nonetheless.