is there a reason for staying with batman-adv 2014 for openwrt 15.05?
our current freifunk leipzig running batman-adv 2015.0 and it seems to work
https://github.com/openwrt-routing/packages/tree/master/batman-adv
vs.
https://github.com/openwrt-routing/packages/tree/for-15.05/batman-adv