These installations are already certified by EASA.

The installation of the 4-blade MTV-16 provides these advantages: Cruise speed increase by 3 knots, and approximately 35 pounds less weight than the original propeller.
The MT-Propeller natural composite blades provide “significant inside and outside noise reduction,” company officials said. They also provide best vibration damping characteristics for almost vibration free propeller operation and have bonded-on nickel alloy leading edges for erosion protection of the blades, according to officials.
Additionally, they have no life limitation and are repairable in case of an FOD.
MT-Propeller holds more than 200 STCs worldwide and is an OEM supplier for more than 90% of the European aircraft industry, as well as 30% of the U.S. aircraft industry.