Were those who had more than four wives commanded to divorce the excess ones after the ruling limiting the number of wives to four was revealed, and does this ruling have retroactive effect?

It has been established that the Prophet, may Allah's prayers and peace be upon him, commanded those who embraced Islam and had more than four wives to choose four and separate from the rest. This occurred with Ghaylan ibn Umayyah al-Thaqafi and Al-Harith ibn Qays al-Asadi.