Historical clue formulations

• Invite qualifier, for short — 2024-10-12
• Party invite inits. — 2021-09-01
• Letters on a party invitation — 2020-10-20
• Invitation qualification — 2019-04-12
• Caveat on a party invitation: Abbr. — 2008-11-17
• "I'm not supplying," on invitations — 1995-11-19
• Party letters — 1993-12-29