Dear list, having the following sample code: \setuppapersize[A4, landscape] \setuplayout[page] \setupinteraction[state=start] \starttext \setupfield[sl][horizontal] [frame=off, width=\textwidth, height=\textheight] \definefield[x][signature][sl] \field[x] I also attach a sample certificate with password ABCabc. The binaries for Windows provided by Artifex do not provide SSL support. I’m on Linux myself, and something like MSYS2 provides binaries with support for Linux (https://packages.msys2.org/base/mingw-w64-mupdf). I wonder whether Homebrew provides mupdf-gl (I cannot say from https://formulae.brew.sh/formula/mupdf). If I try to sign the output PDF with the previous password, using mupdf-gl or "mutool sign" (version 1.2.2), the signature annotation is only viewed by MuPDF, MuPDF-GL and SumatraPDF. On Linux, neither Evince or xpdf can display the signature annotation. On Windows, Acrobat Reader DC doesn’t display the signature annotation, nor it shows any info about the document being signed (BTW, I used another certificate for this). If I open the unsigned document with Acrobat Reader DC and save it, then mupdf-gl can sign the saved document that Acrobat can handle (both annotation and signature info) and Evince and xpdf can display the signature. I guess what might be causing this issue and I’m investigating it. But it would really help, if someone can confirm the issue with MuPDF-GL (or "mutool sign") and Acrobat (Reader or not). Many thanks for your help, Pablo