This version is an update for API node operators. Both the get_account_history and get_account_history_rocksdb plugins now consistently use 0-based indexing of operations. The get_block_api plugin was also rewritten to eliminate excessive mutex locking. A new api call get_block_range(starting_block_num, count) was added to support fetching multiple blocks with a single api call. It was implemented in such a way that it can read multiple blocks in a single disk IO call.