When setting the pdf version so 2.0 (by using the not really documented variable majorversion) I get a warning that objcompresslevel needs a minorversion >4: \pdfvariable majorversion 2 \pdfvariable minorversion 0 \pdfvariable objcompresslevel=1 blb \bye This is LuaTeX, Version 1.10.0 (TeX Live 2019/W32TeX) (format=luatex 2019.3.1) 2 MAR 2019 13:13 restricted system commands enabled. **test-utf8.tex (./test-utf8.tex warning (pdf backend): objcompresslevel > 0 requires minorversion > 4 -- Ulrike Fischer https://www.troubleshooting-tex.de/