We are unable to upgrade to 3.4 until we get a resolution on this topic, or even a hint of what is causing Matomo 3.4 to track twice the number of visits as Piwik 2.16.5.
Our process was to duplicate our existing server (by imaging it) and run the upgrade by the manual upgrade method. Now we’re running both servers side-by-side and our expectation would be that they would track the same numbers it all cases.
This screenshot shows the issue:
We are also tracking this site in GA, which also basically agrees with 2.16.5:
On the top is 3.4 and the bottom 2.16.5. Same date range, same site etc. We’re funneling data to both servers by using the dual tracker method