Historical clue formulations

• Is unobliged to — 2021-12-23
• Is unobliged to — 2018-09-01
• Is unobliged to — 2017-03-12
• Is unobliged to — 2009-08-07
• Is unobliged to — 2005-01-14
• Is unobliged to — 1999-06-30
• Don't have to — 1996-10-13