basic-rails/app/views/devise/mailer/email_changed.html.erb

<p>Hello <%= @email %>!</p>

<% if @resource.try(:unconfirmed_email?) %>
  <p>We're contacting you to notify you that your email is being changed to <%= @resource.unconfirmed_email %>.</p>
<% else %>
  <p>We're contacting you to notify you that your email has been changed to <%= @resource.email %>.</p>
<% end %>