I will argue that Double Field Theory (DFT) can describe some, but not all, alpha'-corrections to the tree-level string effective action. In particular, I will discuss how the first and second alpha'-corrections to the bosonic and heterotic string can be derived from DFT.

It has been known since the 80's that the Green-Schwarz superstring possesses the fermionic kappa symmetry, required for the consistency of the formulation, if the target space is a solution of the supergravity equations of motion. However, contrary to the standard lore and previous claims in the literature, it was recently shown that the converse is not true. Kappa symmetry of the Green-Schwarz superstring implies only a weaker set of equations for the target space fields, which we refer to as generalized supergravity equations. I will describe these equations for the type II case and contrast them with the standard type II supergravity equations which arise as a special case.