A new version of mate-applet-softupd is available from the upstream github repository at: https://github.com/assen-totin/mate-applet-softupd (He doesn't appear to be updating the website at http://www.zavedil.com/mate-software-updates-applet/ any more, so you may also want to change the URL field of the specfile as well.) This stops the applet segfaulting every Friday. (Basically, spawning the backend update-check processes leaks a pipe file descriptor on every check. This happens every 10 minutes. Just shy of a full week later, this causes it to exceed ulimit NOFILE, and the next pipe call fails, which due to a lack of error checking in turn causes an fdopen() call to return NULL, followed by a segfault attempting to use that returned pointer.)
FEDORA-2020-d29f3854f6 has been submitted as an update to Fedora 31. https://bodhi.fedoraproject.org/updates/FEDORA-2020-d29f3854f6
FEDORA-2020-9c0519ab71 has been submitted as an update to Fedora 30. https://bodhi.fedoraproject.org/updates/FEDORA-2020-9c0519ab71
F30 build https://koji.fedoraproject.org/koji/buildinfo?buildID=1427495 tested, fd leak no longer evident.
mate-applet-softupd-0.4.8-1.fc31 has been pushed to the Fedora 31 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2020-d29f3854f6
mate-applet-softupd-0.4.8-1.fc30 has been pushed to the Fedora 30 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2020-9c0519ab71
mate-applet-softupd-0.4.8-1.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.
mate-applet-softupd-0.4.8-1.fc31 has been pushed to the Fedora 31 stable repository. If problems still persist, please make note of it in this bug report.