I am currently writing a relation from the Serbian Wikimedia conference (http://rs.wikimedia.org/wiki/%D0%A2%D1%80%D0%B5%D1%9B%D0%B0_%D1%80%D0%B5%D0%B3%D0%B8%D0%BE%D0%BD%D0%B0%D0%BB%D0%BD%D0%B0_%D0%BA%D0%BE%D0%BD%D1%84%D0%B5%D1%80%D0%B5%D0%BD%D1%86%D0%B8%D1%98%D0%B0) on a Polish chapter wiki. It is difficult to point to resources of our Serbian colleagues because we don't have an interwiki link for "rs".
There is an "sr" prefix already for Serbian Language Wikipedia, but the new country code for Serbia is "rs".
mysql> select * from interwiki where iw_prefix='sr';
+-----------+---------------------------------+----------+----------+
| iw_prefix | iw_url | iw_local | iw_trans |
+-----------+---------------------------------+----------+----------+
+-----------+---------------------------------+----------+----------+
mysql> select * from interwiki where iw_prefix='rs';
Empty set (0.00 sec)
Version: unspecified
Severity: critical
URL: http://pl.wikimedia.org/wiki/:rs:Home page