Great news from the propulsion team. After the engine was tested successfully for a total impulse of 267 kNs in March at the 10kN thrust level, HyEnD encountered problems regarding combustion instability and high frequency oscillations at elevated thrust levels. 
As the rocket is operated in blow-down mode, the thrust continuously decreases during operation. Elevated initial thrust levels are necessary in order to ensure a sufficient initial acceleration when the rocket still contains its maximum propellant load.
After multiple short duration test firings in June and July, the design of the engine was optimized and now allows for stable, smooth, and efficient operation at thrust levels of up to 15kN. At 40 bar chamber pressure, a specific impulse of more than 230s was achieved. In the upcoming weeks, the entire propulsion system will go through final testing as the launch is getting closer and closer.