Do the deadline extensions apply only to members of the U.S. Armed Forces serving in the combat zone?

No. Members of the U.S. Armed Forces who perform military service in an area outside a combat zone qualify for the suspension of time provisions if their service is in direct support of military operations in the combat zone, and they receive special pay for duty subject to hostile fire or imminent danger as certified by the Department of Defense. The Military Family Tax Relief Act of 2003 further applied the deadline extension provisions to those serving in a Contingency Operation, as designated by the Secretary of Defense.