The MakerDAO community has shut down the Single-Collateral DAI (Sai) system as the protocol fully transitions to the new Multi-collateral DAI (MCD or Dai) system.
In Nov. 2019, MCD was activated on MakerDAO as an upgrade to the Dai protocol. While Sai is backed only by ETH collateral, MCD is backed by several types of assets, which currently include ETH, BAT, USDC, and WBTC. The update offered users more collateral options and introduced the Dai Savings Rate, which rewards holders with a variable interest rate paid out in Dai.
The community had always anticipated the eventual shutdown of the Sai system, though with no sense of urgency. But discussions on the topic recently intensified due to market conditions in March, when it became clear that Sai faced significant liquidity issues.
On March 30, Maker Foundation placed a Governance Poll to determine whether to initiate the shutdown. After the community approved the process, the protocol entered into a grace period between April 24 and May 12 for users to migrate their Collateralized Debt Positions (CDP) to MCD. Sai holders were also able to exchange their tokens to MCD on platforms like Uniswap.
Sai officially shut down on Monday. Each Sai holder needs to exchange the tokens for ETH manually through the migration portal.