The old admin email address should be notified of a change to the address

[johnbillion]

In #32430, a notification was added so that users are alerted when their user profile email address is changed.

The same behaviour should be implemented so the old admin email address is notified when the Email Address (single site) or Network Email Address (network admin) fields are changed. This reduces the likelihood of a site or network compromise going unnoticed.

[MatheusGimenez]

Hi, its my first patch. Sorry if i doing something wrong :]

[MatheusGimenez]

Fix email message.

[MatheusGimenez]

Update email message

[MatheusGimenez]

Add @since

[MatheusGimenez]

Move function to wp-admin/includes/misc.php

[MatheusGimenez]

Add @param

[jbpaul17]

This will need review and an owner to land in 4.8.

[ocean90]

Moving to future because beta 1 has been released which means no more commits for any new enhancements or feature requests in this release cycle.

[johnbillion]

39117.8.diff​ expands on the patches by @MatheusGimenez so a notification is also sent to the old network admin email address when the network admin email address changes (on multisite).

Just needs a second pair of eyes, then we're good to go.

[johnbillion]

In 41164:

Options, Meta APIs: Send a notification to the old admin email address when the site admin email or network admin email address is changed.

This reduces the chances of a site compromise going unnoticed, in the same way that the same notifications for user account email address changes reduces the chances of a user account compromise going unnoticed.

Props MatheusGimenez, johnbillion

Fixes #39117

[johnbillion]

In 41167:

Options, Meta APIs: Fix a typo introduced in [41164].

See #39117

[johnbillion]

In 41170:

Users: Update some tests for admin email change confirmation emails after [41164].

See #40015, #39117

[johnbillion]

In 41255:

Options, Meta APIs: Update the multisite unit tests after [41254], [41164], and [41163].

This moves some more previously Multisite-only tests into the main test suite, and makes small adjustments to their assertions.

See #39118, #16470, #39117