The “4th Generation DLE” (4G-DLE) gas turbine burner has been developed at Siemens Industrial Turbomachinery AB in Finspong, Sweden (SIT). The present document describes the design concepts of the 4G-DLE burner; emission performance and fuel flexibility capacity. These features were explored at atmospheric conditions at SIT. High concentrations of H2 and N2 mixed with natural gas were used in the experiments. Emissions (NOx, Unburned hydrocarbons, CO), combustion dynamics and temperature operation range were evaluated. Moreover, operation characteristics of the burner were investigated through forced flashback, flameouts and unfavorable ignition situations. The fuel flexibility concerning H2 stretched up to 90% vol. in a mixture with natural gas. In the case of N2 it was possible to use over 50% vol. mixed with natural gas. The operation was stable in all cases. The 4G-DLE burner showed good NOx emission performance that was linearly dependent on the flame temperature, while CO levels were also low. This fact reveals the high mixing level achieved in the burner. Finally; the burner operated over in a wide flame temperature range (approximately 200 K), showing both good stability and good emission levels.