It may be that some users are using quite old versions that have compatibility problems.

The software is backward compatibile to the previous version, and users who are on the previous version will receive upgrade notifications.  Users on versions prior to the previous version may have difficulties operating in conjunction with users on the current version, particularly if all are using a single centralised (SQL Server) database.

Ideally on centralised (SQL Server) implementations, in particular, all users would be updated at the one time by the IT group.  Any users that miss this will still be able to use ESdat, but will receive update notifications (so they are aware they have been missed).  If these are ignored, and then some time later a futher update is done and these users are still not updated their instance may continue to work, or may not.

When upgrades to the current version are available there is no immediate notification directly to users, a notification is emailed to the IT contacts.  However, if the update is not applied, and a subsequent release comes out (putting users 2 releases behind) users will receive a notification, this would typically mean they are using a version about 2 years old.  In this case we prefer to have discussions with the IT group about how users can be updated a bit more regularly so they can take advantage of the improvements we are continually making to the software.

I've received a similar email from you Dave, so if there are any specific issues that are preventing IT controlled updates I'll follow up offline.