The official Pandora app for Windows Phone has been updated, but does not come with a change log and appears to be a minor version bump. The new release is 18.104.22.168 and we can only assume minor improvements have been bundled. We last covered the release of the official app back in May.
Some reviews on the store have highlighted issues with multiple elements of the experience, so it would be nice if those were addressed. If you happen to notice anything we've overlooked, be sure to shout at us in the comments. You can download Pandora from the Windows Phone Store (Windows Phone 8 only and region restricted). Thanks, Eric, for the tip!