Hi Matt, I'm not sure what the solution is for your system, but here's my configuration:
org-file-apps is a variable defined in `org.el'.
Its value is ((auto-mode . emacs)
("\\.mm\\'" . default)
("\\.x?html?\\'" . default)
("\\.pdf\\'" . default))
I'm on Ubuntu Trusty on this system, and /etc/mailcap is a large file
containing many specific references to opendocument filetypes, etc.
When I export to ODT with "C-c C-e o O", the resulting file opens in
LibreOffice.
Hope this helps.
