Hi,
After updating to Org mode version 9.5.3-g69c588 via Elpa on Emacs 26.3, my Org Agenda view fails with the following backtrace: Debugger entered--Lisp error: (error "rx form ‘regexp’ requires args satisfying ‘stringp’") signal(error ("rx form ‘regexp’ requires args satisfying ‘stringp’")) error("rx form `%s' requires args satisfying `%s'" regexp stringp) rx-check((regexp org-ts-regexp3)) rx-regexp((regexp org-ts-regexp3)) rx-form((regexp org-ts-regexp3) |) #f(compiled-function (x) #<bytecode 0x172a129>)((regexp org-ts-regexp3)) mapconcat(#f(compiled-function (x) #<bytecode 0x172a129>) ((regexp org-ts-regexp3) (regexp org-element--timestamp-regexp)) "\\|") rx-or((or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) rx-form((or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) rx-to-string((or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp)) t) #f(compiled-function (&rest regexps) #<bytecode 0x16fa711>)((or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) (rx (or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) (if (eq extended (quote agenda)) (rx (or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) org-ts-regexp3) (if extended (if (eq extended (quote agenda)) (rx (or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) org-ts-regexp3) org-ts-regexp2) (let* ((regexp (if extended (if (eq extended (quote agenda)) (rx (or (regexp org-ts-regexp3) (regexp org-element--timestamp-regexp))) org-ts-regexp3) org-ts-regexp2)) (pos (point)) (match\? (let ((boundaries (org-in-regexp regexp))) (save-match-data (cond ((null boundaries) nil) ((eq extended ...) t) (t (or ... ...))))))) (cond ((not match\?) nil) ((= pos (match-beginning 0)) (quote bracket)) ((= pos (1- (match-end 0))) (quote bracket)) ((= pos (match-end 0)) (quote after)) ((org-pos-in-match-range pos 2) (quote year)) ((org-pos-in-match-range pos 3) (quote month)) ((org-pos-in-match-range pos 7) (quote hour)) ((org-pos-in-match-range pos 8) (quote minute)) ((or (org-pos-in-match-range pos 4) (org-pos-in-match-range pos 5)) (quote day)) ((and (or (match-end 8) (match-end 5)) (> pos (or (match-end 8) (match-end 5))) (< pos (match-end 0))) (- pos (or (match-end 8) (match-end 5)))) (t (quote day)))) org-at-timestamp-p(agenda) org-agenda-get-timestamps(nil) org-agenda-get-day-entries("/home/cm/org/pro.org" (4 18 2022) :deadline :scheduled :timestamp :sexp) apply(org-agenda-get-day-entries "/home/cm/org/pro.org" (4 18 2022) (:deadline :scheduled :timestamp :sexp)) org-agenda-list(nil) funcall-interactively(org-agenda-list nil) call-interactively(org-agenda-list) org-agenda(nil) funcall-interactively(org-agenda nil) call-interactively(org-agenda nil nil) command-execute(org-agenda) Yours, Christian