A pilot approved to update the GPS data base would enter the action in the MR and the calendar date of the next due update. As the MR could be valid for 12 months, there could be quite a few of these entries.
Now, question - if the aircraft runs past the due date of the next GPS update can it fly? Probably, but presumably an entry would then need to be made that the GPS was not to be used for navigation. Presumably, THAT particular entry would be made by a LAME. I know how it works in MEL - land, but this antiquated MR form that is still in use in GA is something else. Educate me.