Syscoin 4.1.2 Mandatory Upgrade
Users of Syscoin 4.1 clients or below may experience issues in which blocks get stuck. All Syscoin users should upgrade to 4.1.2. to prevent these issues.
On block 318734, a mempool transaction (Asset Update) was mined which was stuck in the mempool of the network when it was running 4.0.x nodes.
The network was meant to be backwards compatible but 4.0.x nodes do not have knowledge of the new methods of constructing transactions, saving 50% bandwidth costs in 4.1.x. Since 4.0.x is not forwards compatible, these transactions were simply not mined until miners upgraded to 4.1.x at which point the stranded transaction was put into block 318734 causing all 4.0.x nodes to halt on the consensus of that specific transaction.
This was the result of our diligence in testing which was meant to test that 4.1.x would be compatible with legacy transactions and that 4.0.x would also reject new transactions in consensus.
As the mempool had this stranded transaction, as soon as our nodes were upgraded and we ran our clients, it sent the mempool transaction to the miner causing 4.0.x nodes to halt.
In order to fix, the 4.0.x nodes can simply upgrade to 4.1.2 and reindex, or:
to sync back to the tip.