The Only Rabbinic Holiday Celebrated by Karaite Jews

I find it interesting that virtually every Karaite calendar, since the first one was printed in 1835, lists the extra-biblical holiday of Simchat Torah

See this clip starting at the 35:36 mark See also my article on the Beta Israel (Ethiopian Jews)  and Simchat Torah here.

This is a calendar from the Karaite community, dated Oct. 1959

Apparently this has been true since the 15th century

From Harav Ha-dayan Yosef ("susu") Elgamil's adaptation of Mourad El-Kodsi's english book: