In 1971, the Military Selective Service Act was further amended to make registration compulsory; all men had to register within a period 30 days before and 29 days after their 18th birthday. Registrants were classified 1-A (eligible for military service), 1-AO (Conscientious Objector available for non-combatant military service), and 1-O (Conscientious Objector available for alternate community service). Student deferments were ended, except for divinity students, who received a 2-D Selective Service classification. Men who were not classifiable as eligible for service due to a disqualification were classified 1-N. Men who are incapable of serving for medical or psychological unfitness are classified 4-F. Draft classifications of 1-A were changed to 1-H (registrant not currently subject to processing for induction) for men not selected for service after the calendar year they were eligible for the draft. (Note: these – and other – draft classifications were in place long before 1971.) Also, draft board membership requirements were reformed: minimum age of board members was dropped from 30 to 18, members over 65 or who had served on the board for 20 or more years had to retire, and membership had to proportionally reflect the ethnic and cultural makeup of the local community.