I don't have cos_occ market for some reason. I installed the calendar app manually via the browser. The problem is that the calendar data from 8.2.4 is gone after the upgrade to 10 and before the installation of calendar for 10. According to owncloud, upgrading from 8 -> 10 isn't supported.

I would like to have the version 8 repo available. I am thinking that I will need to follow the upgrade path, 8.2.4 -> 9.x -> 10.0.9, export the database, wipe the upgraded install, re-install owncloud from ClearOS marketplace, then re-load the database.