Riak Enterprise Upgrade

Hi, Could anyone answer below queries with regard to upgrade? I am currently running Riak V1.4.11 enterprise version with multi-data center replication. I want to upgrade to Riak 2.0.6 version. 1. Should i follow Rolling upgrade process as in below? http://docs.basho.com/riak/latest/ops/upgrading

put failing with error

Hi, I run bash bench. i used riakc_pb_text.config in examples.. put operation fails with below error: [error] Supervisor basho_bench_sup had child undefined started with basho_bench_worker:start_link(basho_bench_worker_2, 2) at <0.96.0> exit with reason normal in context child_terminated 17:50