On 22/10/15 15:43, Luke Dashjr wrote: > BIPs should in general not be > designed around current software I strongly disagree with this statement. There is a version byte in the payment code specification for a reason. Version 1 payment codes are designed to be deployable by wallet implementers today, without requiring them to wait on any network-level changes whatsoever, which includes IsStandard() redefinitions, or yet-to-be-invented-and-deployed filtering schemes. As far as I know, multi-push OP_RETURN outputs are not standard transactions and so wallet users can not rely on transactions containing them to be relayed through the network, therefore any improvement to the protocol which requires that feature is not appropriate for version 1. When additional capabilities are deployed in the network such that Bitcoin users can rely on their existence, that would be a great time to specify a version 2 payment code that uses those features and encourage users to upgrade (which should be a fairly smooth process since their actual keys don't need to change).