The duplicate shares problem is now fixed and rieMiner seems now be usable for pooled mining. Miners, please try rieMiner and give some feedbacks.
And lucky you XPoolX, I even found a block during testing...
I haven't taken anything out so if it is in Bitcoin it should be in the new code. The '3' and '2' come from the SCRIPT_ADDRESS that gatra set.
I did not know that these "3" addresses already existed in 2014. But in this case, we should change the prefixes anyway to avoid confusion with Bitcoin "3" and "bc1" addresses.
Edit: I finished syncing and tested quickly rieMiner with your wallet via GetBlockTemplate. Unfortunately, I am getting "CheckProofOfWork() : not valid pow" messages in Testnet when finding blocks, but the miner seems to be able to extract correctly the mining information (else, it would not mine anything, yet it is actually working and finding/submitting things).
The GetBlockTemplate command in 0.16 seems to give the same results for the needed fields (previousblockhash, coinbasevalue, bits,...), so I think that the miner should still have been compatible without any changes. The version changed, but submissions are still rejected if I hard change it to 2. Can you see in your side what might have changed when the wallet receives proof of work?