eMail-notifications: take out logo & title

Hi,
is it possible to take out the logo and the title in the eMail notifications? My users don´t like it they complain it takes away space without giving any added value.

I am talking about the PILOTEN logo and the title "NEUE UNTERHALTUNG" (screenshot) and all other messages like you have a reply, etc.

I guess I need to take out some PHP code somewhere?

Is there a way to make this update-proof - otherwise, changes need to be repeated after next update?

Thanks