Answer: The Sabbath day will not change. Malachi 3:6 (KJV), "For I am the LORD, I change not." Christ’s inaugural public address to the people is recorded in Luke. Luke 4:16, "So He came to Nazareth, where He had been brought up. And as His custom was, He went into the synagogue on the Sabbath day, and stood up to read. The very first law that He begins to make clear is the Sabbath day by reinforcing the important custom and commandment."
If the Sabbath was the first law revealed to the children of Israel and again reinforced by the actions of Christ and the Apostles it does not make any sense that it has now somehow changed.
When a new heaven and new earth are established, all of the commandments will still be in force. Isaiah 66:22-23, "'For as the new heavens and the new earth Which I will make shall remain before Me,' says the LORD, 'So shall your descendants and your name remain. And it shall come to pass that from one New Moon to another, and from one Sabbath to another, all flesh shall come to worship before Me,' says the LORD."