Recently, I updated my personal certificate. Then I wanted to sign a libreoffice document.
I followed the instructions from Part 1 to Part 4. Both Thunderbird and Firefox are displaying the correct, up-to-date certificate. But Libreoffice (5.1.6.2, xenial4) shows still only the outdated one (with the Firefox:default option) or nothing (with thunderbird:default option).
Edit: I've already found out the reason: different cert and key file formats used by mozzila resp. LO, in place since spring 2018. But no way how to solve it :-O