New article by Jürgen Habermas:
"Von der formalen Semantik zur transzendentalen Pragmatik – Karl-Otto Apels ursprüngliche Einsicht" [pdf]
("Topologik – International Journal of Philosophy, Educational and Social Sciences" no. 26, 2019/2020, pp. 66-88.)
See also the other essays in “Topologik” on Karl-Otto Apel, including contributions by Rainer Forst, Edmund Arens, Hauke Brunkhorst, René von Schomberg, Dietrich Böhler, Vittorio Hösle, Jon Hellesnes, Matthias Kettner, Marcel Niquet, and Piet Strydom.
Update:
An English translation of the paper:
“From Formal Semantics to Transcendental Pragmatics: Karl-Otto Apel’s Original Insight”, Philosophy & Social Criticism vol. 46, no. 6 (2020), pp. 627-650.