Org-mode version 8.0.5 (latest)
Test done with this command: emacs -q --load ~/t/org-test-final.el Contents of ~/t/org-test-final.el: (setq package-load-list '((org t) (org-plus-contrib t))) (setq org-export-section-number-format '((("I" ".")) . ".")) (package-initialize) (find-file "~/t/simple.org") Contents of ~/t/simple.org: * one ** two *** three In the test emacs session, press C-c C-e (org-export-dispatch) then press h o to open the exported html in the browser. The section numbers are shown as 1 and 1.1 and 1.1.1 when they should be, I guess, I. and I.I. and I.I.I. Same result with this too: (setq package-load-list '((org t))) (custom-set-variables '(org-export-section-number-format (quote ((("1" ".")) . ".")))) (package-initialize) (find-file "~/t/simple.org") C-h v cannot find the variable org-export-section-number-format but M-x customize-group RET org-export-general RET shows its documentation, after that C-h v shows it is defined in org-exp.el which is a file bundled with Emacs, and is not part of the latest org package.