Well first of all Electrum doesn't show update notifications at all. If it were to start now it'll only muddy the waters even more

Second the message is by the server you are connected to and the electrum company doesn't control those servers. If it did then they could simply replace the messages with numerical error codes and then the client could display a limited set of meaningful error messages depending on the error code instead of arbitrary messages from the server. This is the proper fix they talked about.

In the meantime the electron cash approach might work where they attempt to parse the message from the server and then replace it with a legit error message. Another suggestion was to hide the message from the server under a read more button so that those who actually cared could read it while your regular users won't bother and therefore won't be phished.