New mode coming in Season 4. Basically, raids with a M+ affix.
For Season 4 raiding, we’re imagining adding a progenitor-themed affix system to infuse some new mechanical twists into Castle Nathria, Sanctum of Domination, and Sepulcher of the First Ones. Our intention here would be to make all three raids relevant in Season 4, with increased difficulty and more powerful levels of raid loot dropping throughout all of them.
Coming Later This Year: Shadowlands Season 4