Md. Rule 6-432
Rule 6-432. Order to Answer; Register's Notice and Service
Within five days after the filing of the petition to caveat, the Register shall:
(a) issue an Order to Answer requiring the personal representative appointed as a result of the probate of the will or codicil or both being challenged, if one is currently serving, to respond to the petition to caveat within 20 days after service;
(b) serve the Order together with a copy of the petition on the personal representative by first class mail, unless the petitioner requests service by the sheriff;
(c) serve on each interested person a copy of the Notice of Caveat by first class mail, and if no personal representative appointed under the will or codicil or both is currently serving, furnish with the notice a copy of the petition to caveat; and
(d) publish the Public Notice of Caveat once a week for two successive weeks in a newspaper of general circulation in the county where the petition to caveat is filed.