I have an old Piwik 1.11.1 installed and being actively used by ~80 websites - although it contains old data on ~1,000 websites.
I would like to import all this data to a new machine with a clean installation of Matomo 3.3.3, while taking into consideration the fact that these ~80 sites are online and that I prefer minimal downtime and data loss.
I have the sites using the PHP tracking code (the Piwik URL is not exposed on the client side).
What are the steps I’ll need to take in order to import the data from the old Piwik installation to the new Matomo installation, and migrating the tracking codes on the relevant sites?
Thanks a lot!