The Braunschweig Icing Wind Tunnel is in the process of upgrading its capabilities for App. O/ SLD (supercooled large droplet) icing conditions. First measurements have been conducted by TU Braunschweig and DLR in January 2020 testing a new spray system and deploying several cloud droplet sensors inside the wind tunnel. The preliminary results are looking very promising for both the icing wind tunnel upgrade and the sensors. During SENS4ICE further detailed analysis is conducted to characterize the droplet spectrum and compare it to atmospheric icing conditions.