@neurolit suggested this approach for org-version dependent links in the mu4e repo. I should have thought of that too! Its totally robust.
(if (fboundp 'org-link-set-parameters) (org-link-set-parameters "mu4e" :follow #'org-mu4e-open :store #'org-mu4e-store-link) (org-add-link-type "mu4e" 'org-mu4e-open) (add-hook 'org-store-link-functions 'org-mu4e-store-link)) -- Professor John Kitchin Doherty Hall A207F Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213 412-268-7803 @johnkitchin http://kitchingroup.cheme.cmu.edu