[Milhouse]

Weekly Linux 5.3-rc2 build #0730x: Generic

Will there be HDR for nuc7i5bnh (kabylake) with kernel 5.3?

Probably not, at least initially it's only for Gen 11 which means Ice Lake/Gemini Lake (and later). There may be technical limitations (LSPCON and lack of native HDMI 2.0 support) that make it impossible to support HDR on older generations.