What are the differences between RIPv1 and RIPv2?
RIPv1 uses a standard route. Occasional updates do not have subnet information and no support for VLSM. This limitation makes it impossible to have subnets of different sizes within the same network category. In other words, all subnets in the network class should be the same size. There is also no router authentication support, which makes RIP vulnerable to various attacks.
RIPv2 is a vector distance route protocol defined in RFC 1723. As a phaseless protocol, it means, it included a subnet mask and network addresses in its router updates.
