As you may know, the Timestat Block was developed and upgraded for Moodle 2.5 and 2.6, however when we contributed it to Moodle.org it was, sadly, rejected. See below for the reason stated by Lukasz Sanokowski who upgraded the block.
They have some issues about this app (which were not issues at all with previous upload of 1.9 version), and the most difficult is that they don’t like that timestat is changing mdl_log table structure (because there is added a field). At this moment I don’t see a simple workaround of this. Moodle HQ policy is now much more stricter (that is good because it brings high software quality).
We agree about the higher level of scrutiny that mods are given now at Moodle.org. But that leaves us with a great (fully functional) Timestat Block to measure student time on site with no repository to host it.
So rather than continue sitting on the code, here it is: Download TimeStat Block
What I would love is for someone to propose a solution to fixing the mdl_log table structure issue and let me know how I can help get it released to the community once and for all. In my opinion, tracking student usage by time is something that Moodle is currently lacking the capacity to do, and many other courseware providers and learning management systems are instituting the means of tracking time on site and within activities and resources. The Timestat Block establishes a means of doing just that.