Are integer indexes in 2i 64-bit or 32-bit?

I apologize for asking this question if it's an FAQ or is documented somewhere, but I don't see anything specific mentioned about the size of integer indexes in 2i: http://wiki.basho.com/Secondary-Indexes.html I certainly could dive into to source code to answer this question, but in case some

Rolling upgrade from 1.2 to 2.0

Could someone please point me toward some authoritative documentation on whether a Riak cluster running version 1.2 can be upgraded in rolling fashion to 2.0 directly, without going through an intermediate release? We generally held back on 1.4 due to some of the growing pains we perceived aroun