fruux/sabre-vobject — pull request #154 by evert (2014-11-04 00:56:53+00:00)
Title: Support for converting ANNIVERSARY

vcard 3 -> 4
------------

Find all X-ABDATE and X-ANNIVERSARY properties, and merge the ones with identical values. Convert all of these to ANNIVERSARY.

vcard 4 -> 3
------------

Convert ANNIVERSARY to both X-ABDATE and X-ANNIVERSARY.