Since April my course participants who have a Yahoo account (also those at two of the private universities here) seem invisible to the Moodle.

When they upload work, the Moodle doesn't tell us that they have (nor does it confirm to them) and when they ask questions in the forums it doesn't send these through, nor messages if they message me directly from inside the course, though these last are there waiting when I next log in. It is making courses very hard to manage (as now I have to spend checking time in each separate Moodle every day to see if any of them did any of those things). My Moodle admin person says 'there is a problem', but he also says I just have to live with it - can anyone point me to information to give to him so he can fix / change / solve whatever is causing it ?

I think we are version 2.6 (not sure - how do I check that ?)
I didn't know which components to check in the list below as it affects assigments, forums and messaging.

I've tried to search (there used to be forums to search in - sorry if I am in the wrong place) and can't turn up anything similar.