Email a single Admin when a user changes Email

I can't find anything about this anywhere else.

How do I get a notification when a user changes their email address? I get notification of new sign ups only.

There is no notification for that. You'd need to use CB Auto Actions acting on the onAfterUserUpdate with an Email action then under Conditions use the following.

[var1_email] Not Equal To [var2_email]

Then for To supply your email address manually. This should email you if a users email address changes.

Guess I'll have to get my head around CB Auto Actions then. I would have thought this would have been a pretty standard requirement as a standard function?

Emailing about a field changing isn't very standard. Frankly it's just spam. An on-site notification system would be better. We've plans for per-field approval as well (currently only available for image fields). Good news is it's a pretty simple configuration. Below should work.

Global
Triggers: onAfterUserUpdate
Type: Email
User: Automatic
Access: Everybody
Conditions
1: [var1_email] Not Equal To [var3_email]
Action
To: Your Email Address
Subject: Your Email Subject
Body: Your Email Message

Substitutions are supported in the To, Subject, and Body as well. So if you want the username of a user you could do [username]. var1 is the new user object (after their change) and var3 is the old user object (before their change).

Additionally you could try CB Profile Update Logger as believe it has some notification usage built in.

www.joomlapolis.com/addons/cb-profile-update-logger