The locale names for Serbian that have been recently committed to trunk are wrong, they don't follow the right ISO standards ( see http://ez.no/doc/ez_publish/technical_manual/4_0/features/multi_language#locales ). They should be fixed before doing any final releases.

Note: before eZ Publish 3.8 there was a ser-SR locale (wrongly named), but it seems like it disappeared since 3.8.