However, Gavin Andresen disagreed and argued that compatibility with existing transaction signing software and hardware should be considered. He believes that any hard fork proposal should support a reasonable number of reasonable-size old-sighash transactions to allow for smooth transitions of wallet software and hardware, and to support anyone who may have a hardware wallet locked away in a safe deposit box for years. While he acknowledges the need to consider hardware that cannot be easily upgraded, wallets that can upgrade should do so to maximize chain divergence and will likely have to upgrade to know a new header format anyway. He suggests that changing a transaction version would be trivial and only require a few extra lines of code. The discussion took place on January 26, 2017 at 12:21:37 PM EST.