In the past few months account versioning was a topic of importance due to EIP-615 requiring it. Additionally it could wall off other changes (such as gas changes) to minimize protocol update effects on existing contracts.
EIP-1702 was the most reviewed option.
Some of discussion took place on EVM instruction set versioning, https://github.com/sorpaas/EIPs/issues/2 and https://github.com/sorpaas/EIPs/issues/6, but mostly it was discussed on the AllCoreDevs gitter channel.
Created this topic here to have a single place to discuss versioning, because tracking all these places became a burden, at least to me.