According to Foresight News, MakerDAO founder Rune Christensen responded to the discussion about "DAI is adding a freeze function". Christensen said that DAI will continue to function as before and can still be used. Upgrading to USDS is optional, and only USDS will have a freeze function. DAI is an immutable smart contract and cannot be changed. In fact, the new protocol will not have a freeze function at launch, only the ability to upgrade. This means that future governance can decide how to implement a mechanism similar to the freeze function based on the consideration of all data to prevent various risk factors as much as possible.