The ODT and JabRef exporters can now be with Emacs Package Mananger's M-x list-packages. The package is available at https://raw.githubusercontent.com/kjambunathan/org-mode-ox-odt/master/elpa/. See below for a typical configuration.

(custom-set-variables
 '(package-archives
   (quote
    (("gnu" . "https://elpa.gnu.org/packages/")
     ("ox-odt" . "https://raw.githubusercontent.com/kjambunathan/org-mode-ox-odt/master/elpa/")))))

When you install ox-odt from the above archive, it will upgrade your Org to 9.1.14, if needed. Once you have installed the ox-odt package and restart your Emacs. Run M-x locate-library RET org and M-x locate-library RET ox-odt and ensure that you see something along the following lines.

Library is file ~/.emacs.d/elpa/org-9.1.14/org.elc
Library is file ~/.emacs.d/elpa/ox-odt-9.1.14.145/ox-odt.elc

After you export an Org file to ODT, look at your *Messages* buffer and ensure that the ODT exporter *uses` style and schema files from the ELPA package.