SolveDelayed

SolveDelayed is an obsolete option to NDSolve. The option "EquationSimplification" should be used instead.

Examples

(* Use "EquationSimplification" instead *)
NDSolve[{y'[x] == y[x], y[0] == 1}, y, {x, 0, 1}, 
  Method -> {"EquationSimplification" -> "Residual"}]

Please visit the official Wolfram Language Reference for more details.