Relax OP_RETURN standardness restrictions

The inquiry from Boris Nagaev delves into the technical aspects of modifying Bitcoin's consensus rules, specifically questioning the implications of removing the Segregated Witness (SegWit) discount. The premise of the question hinges on understanding the nature of blockchain protocol updates and their classification as either a hard fork or a soft fork. A hard fork represents a significant change to the network's protocol that renders previous blocks or transactions invalid unless updated to the new version, leading to a permanent divergence in the blockchain unless all participants agree to the upgrade. Conversely, a soft fork is a backward-compatible update that tightens the rules without invalidating previous transactions or blocks recognized by old nodes.

Nagaev's question underscores a fundamental aspect of blockchain technology: the distinction between tightening and loosening consensus rules. His query suggests that removing the SegWit discount would constitute a tightening of consensus rules. Under the current framework, blocks validated with the SegWit discount are considered legitimate. However, if the discount were removed, these previously valid blocks would become invalid under the new ruleset, hence necessitating a hard fork. This scenario illustrates the complexities involved in blockchain protocol modifications, highlighting the importance of consensus among network participants to maintain the integrity and continuity of the blockchain.

The discussion also touches on the broader implications of such a change for the Bitcoin network. Implementing a hard fork to remove the SegWit discount would require unanimous agreement from all network participants to avoid splitting the blockchain. This scenario exemplifies the challenges faced by decentralized networks in implementing protocol changes, where the need for widespread consensus can often hinder or slow down the adoption of potentially beneficial updates.