A new scintillating fibre (SciFi) tracker is being installed and commissioned as part of the current LHCb Upgrade. The high radiation dominated by fast neutrons reduces the over-all light yield of the detector in the course of LHC Run 3, challenging high hit detection efficiency. The foreseen replacement of the inner fibre mat modules during the next long shutdown (2025 - 2027) requires to exchange the photodetectors. The current R&D is directed to develop microlens-enhanced silicon photomultipliers (SiPMs) to improve photon detection efficiency. The first prototypes have been produced based on the outcome of dedicated simulation studies, and the results for the light yield measurements are presented.