Happy New Year and good afternoon, Since some l3kernel update in December I am getting kernel/invalid -variant warnings, as in * LaTeX warning: "kernel/invalid-variant" * * Variant form 'cF' invalid for base form '\tl_if_blank:nF'. It is issued for the line of code \cs_generate_variant:Nn\tl_if_blank:nF{cF} that used to work without warning before. Which is the correct method for generating variants of conditionals? Alexander