o Minor features:
   - Increase the maximum number of bits for the IPv6 virtual network prefix
     from 16 to 104. In this way, the condition for address allocation is less
     restrictive. Also, the variable max_bits is called max_prefix_bits,
     making it clearer the meaning of the condition (bits > max_prefix_bits).
     Closes ticket 20151; feature on 0.2.4.7-alpha.