Hello all,

increasingly, I need URL and DOI BiBTeX entries to cite particular types
of publications.  Some BiBTeX styles now recognise these but the current
BiBTeX exporter in org does not export these.  I have added :url and
:doi entries to the list of optional entries to export when present to a
selection of the publication types.

I think this is not a breaking change but who knows...

-- 
: Eric S Fraga via Emacs 28.0.50, Org release_9.4.6-571-gc591be
: Latest paper written in org: https://arxiv.org/abs/2106.05096