What Does Pope Francis Mean by Saying that Doctrine Progresses?

In August 2023, Pope Francis reportedly criticized Catholics who “look backward”, longing for the church of yesteryear. He reminded them that Catholic doctrine “progresses, expands, and consolidates with time and becomes firmer.” To bolster his point, he quoted the fifth-century theologian Vincent of Lérins, who said that doctrine is what the church teaches “everywhere, always, and by all.” Pope Francis’ words reflect the theology of tradition. How can Catholics believe that doctrine both remains the same and progresses?