[NTG-context] Error concerning "pdfmapline"

Hello All! Using: LuaMetaTeX, Version 2.00.0 ConTeXt ver: 2019.04.13 17:25 MKIV beta fmt: 2019.4.15 with following MWE: -------------------------------------------------- \pdfmapline {yfrak unsupported cs \pdfmapline mtx-context | fatal error: return code: 256 I'm using the above "\pdfmapline" command since years. Now it gives an error even when it isn't used in the text. "yfrak.pfb" is in the same directory. Are there any hints, please? Rudolf