On the testnet requirements are pretty minimal - you shouldn’t need to keep shared memory in RAM, so 4gb is probably more than sufficient for a seed, witness, or maybe even full node. You might need more than 4gb to build steem but if you use executables pulled from our official docker image you could avoid building.
On the main net, HF20 requirements should remain the same as they are now.
On the testnet requirements are pretty minimal - you shouldn’t need to keep shared memory in RAM, so 4gb is probably more than sufficient for a seed, witness, or maybe even full node. You might need more than 4gb to build steem but if you use executables pulled from our official docker image you could avoid building.
On the main net, HF20 requirements should remain the same as they are now.