Building codes change. Autodesk releases service packs and hotfixes for Robot 2021 to align with the latest ACI 318-19 or Eurocode 2 updates. A cracked version cannot be updated. You will be designing future structures using outdated, potentially illegal standards.
For high-rise projects, the 2021 version allows for defining primary local X-axis directions for core walls, facilitating easier visualization of reduced forces and moments in diagrams and tables. Building codes change