I've been using Emacs 25.0.92 for a while and noticed that Gnus has
started to display attached pdf files with doc-view-mode (inside Emacs)
instead of launching an external viewer. In mailcap-mime-data variable I
have external viewer (Okular) first for the application/pdf MIME type
but Gnus doesn't want to respect that.

How do configure Gnus to use external viewer for attached pdf files?

-- 
/// Teemu Likonen   - .-..   <https://github.com/tlikonen> //
// PGP: 4E10 55DC 84E9 DFF6 13D7 8557 719D 69D3 2453 9450 ///