Code for ethereum’s upcoming hard fork, dubbed Constantinople, was set to be activated on Ropsten at block number 4,230,000.
what happened :
- Ropsten stalled at block 4,299,999 as miners did not update to the new code.
- A bug was discovered by security lead for the Ethereum Foundation Martin Holst Swende, one which caused two different iterations of the same software upgrade to run on testnet.
- Consesus issue seems to have been different implementations of EIP-1283, SSTORE opcode SSTORE opcode between Parity and Geth.
- Mainnet launch is delayed to 2019.
- Never fork on weekends
- Make bug fixes on the relevant clients and converge to the geth chain again.