They don't use the language, but it appears that May 1 begins a sunrise period for existing name holders followed by a September landrush.
It sounds like you need to own a .mx name in order to participate in the sunrise. As a trademark name holder I wonder whether there is another way to get in on the sunrise of this second level domain.
Announcements are supposed to be made on [nic.mx...] but you'll need to read Spanish.
.mx for mail server appeals only to geeks IMO, people just want to get mail, they don't know the inside