What size diameter is the cut-out on the sub-floor for the KERDI-LINE-VARIO drain outlet?

The subfloor template for KERDI-LINE-VARIO is 3 ½” (88.9 mm) but the max is 4” (101.6 mm). It’s always a good idea to refrain from resorting to the maximum size opening as that way there’s still room for corrections if ever needed.