TL;DR the 9 boundaries:

1. Flow of phosphorus & nitrogen into the environment (exceeded)
2. Atmospheric CO2 (exceeded)
3. “Radiative forcing”, the balance of thermal energy absorbed by the sun and lost to space (exceeded)
4. “Novel entities”, artificial chemicals eg microplastics and PFAS forever chemicals (exceeded)
5. Land use leading to forest loss (exceeded)
6. Freshwater use (exceeded) <— this is the latest boundary that has recently been crossed
7. Ocean acidification
8. Atmospheric aerosol loading
9. Ozone depletion

Edit: It should also be said that the reason we’ve crossed boundary 6. Freshwater is because they’ve changed the way they measure it. Now it includes “green water”, ie water that is available to plants but doesn’t enter into aquifers, and it primarily reflects a decline in this green water availability rather than in surface and ground water.