In Devise::Mailer#email_changed, the new email might be in the email attr.
See: https://github.com/plataformatec/devise/blob/master/app/views/devise/mailer/email_changed.html.erb
%table.input{ align: 'center', cellspacing: 0, cellpadding: 0 }
%tbody
%tr
- %td= @resource.unconfirmed_email
+ %td= @resource.try(:unconfirmed_email) ? @resource.unconfirmed_email : @resource.email
%table.email-table{ cellspacing: 0, cellpadding: 0 }
%tbody
<%= t 'devise.mailer.email_changed.explanation' %>
-<%= @resource.unconfirmed_email %>
+<%= @resource.try(:unconfirmed_email) ? @resource.unconfirmed_email : @resource.email %>
<%= t 'devise.mailer.email_changed.extra' %>