In short: I'd love to understand how to detect if a transaction failed before the Byzantium fork.
Explanation: After the Byzantium fork it's easy to understand if a transaction failed or not, I just need to check the property 'status' which is 1 if successful or 0 if not.
But before Byzantium it looks quite complicated (or not possible at all with 100% certainty?). I saw explanations suggesting to check the 'root' property in the transaction receipt or compare the gas in the transaction receipt and the transaction but I do not think it's reliable.
Any idea on how to do it?