“…Recently, we have proposed multistep collocation methods [13][14][15][16] and two step almost collocation methods [13,17,18], where the collocation polynomial depends on the approximate solution in a fixed number of previous time steps, with the aim of increasing the order of convergence of classical one-step collocation methods, without additional computational cost at each time step, and at the same time obtaining highly stable methods. This idea has been already proposed for the numerical solution of ODEs [19][20][21] (see also [11], Section V.3), and afterward modified in [12], by also using the inherent quadratic technique [22][23][24]. We also underline that they have high uniform order, thus they do not suffer from the order reduction phenomenon, well-known in the ODEs context [9].…”