Hi All,
As reported in MDL-71156, there is an issue with an upgrade step, introduced in MDL-67494. Please also see the note in the last integration exposed post.
Please avoid upgrading to 3.9.5 or 3.10.2 until this issue is resolved.
During the upgrade some calendar events are corrupted.
I apologise for the inconvenience this may have caused for those sites who have already upgraded.
We are currently working on a fix for this issue and will update this discussion when that is available.
Sander