The update distribution is for both Windows and Linux. It's free to customers with a current maintenance agreement. The whats_new.html file in each distribution gives you a quick overview of the release, and the resolved_workitems.html file lists specific tracker issues that are addressed. (You can access these files online in the Documentation tab of each product's download page on the website: ALM, Requirements. 2.0, Track & Wiki).
Full installation downloads
Anyone who would like to download the latest release to make a clean installation for evaluation or for other reasons, here are links to the download pages: