Adds "pooledtx" (number of transactions in memory pool), "currentblocktx" (number of txns in the last block created), and "currentblocksize" to the output of the JSON-RPC 'getinfo' method. Adds "block_hash" and "block_index" to transactions shown by 'listtransactions' and similar JSON-RPC methods.
Been using this since 0.3.21 without issues.