There was a report going around on 2 vulnerabilities to POS coins. I/O Coin base is POS 2 and we upgraded to our own POS CIPHER, so for the record the IOC dev team tested Spent stakes & Stake cycling.  Result in other net nodes was;                                                      

Spent Stakes Test ---- ERROR: ConnectInputs() : 2a02f14637 prev tx already used at (nFile=1, nBlockPos=9382, nTxPos=9529)

Stake Cycling Test ----- ERROR: ConnectInputs() : f1e663bedc prev tx already used at (nFile=1, nBlockPos=3880, nTxPos=4889) ERROR: Reorganize() : ConnectBlock 93a9b61fb53dc9b768c8 failed InvalidChainFound: invalid block=6eafb7bcb4c1c52ef1a5  height=130  trust=6387706109 blocktrust=661321531 date=01/23/19 17:23:25


Spent stakes & Stake cycling are both checked out and rejected in our testnet chain