Piwik no longer works after update to 1.11.1

After update to 1.11.1 piwik just stopped recording new visits.

I still have all the data from before the date of update but eveer since the update no new visits are tracked.

I ran the manual php command line update for the database, after automatic update from the browser.

ANy ideas, I am now uploading older version again, to see if that tracks visitors again.

After uploading 1.10 it tracks visitors again...

Then tried again the automatic updat from the browser and it stopped working again, so now reverting to 1.10 again and will leave it at that until the problem is clear.

Anyone any ideas?