Hi Peter,
Product Marketing has no plans for Mesh in the entry-level positioned 802.11n 2x2:2 R300 model AP.
Mesh is supported in above level models, R500 802.11ac 2x2:2, and R600 802.11ac 3x3:3 stream models,
and higher platform R700 (802.11ac wave 1), R710 (802.11ac wave 2) 4x4:4 stream APs.