deleted lesson plans after upgrade

Upgrade is brilliant; solving lots of little gripes I had (like the events at the top of the planner page in particular and the timeline is very helpful).

As I tinkered with timeline I suddenly noticed that almost all the lesson plans in September and October (up to the half-term) have vanished, just empty boxes. Bizarrely, all apart from two individual periods. After half-term everything is back to normal.

I backed up before upgrading, but all the back-ups have those periods missing too.

Any ideas where they have gone?

Hello HughP,
Sorry I missed your post.
I'm guessing the update had nothing to do with this, if by any chance you have an older backup, send it over (support@idoceo.net) and we'll give it a look. Even a recent one would do, just tell me the a particular class where this is missing and we'll work it out.