If you believe you are running the most up to date kernel from your OS supplier (with backported fixes) you might want to try bypassing the check. I know I would! This is the issue where the check was added. I believe could just remove or comment out the exit command in your ./launcher script, in this paragraph:
# At least minimum version
if compare_version "${kernel_min_version}" "${test}"; then
echo "ERROR: Kernel version ${test} not supported, please upgrade to at least ${kernel_min_version}"
exit 1
fi
If, as a result, the upgrade still fails, then you will need to find a way to run your Discourse on a newer kernel.
(It’s quite possible this advice will be felt to be off-message, but I think what’s happened is that we have a check for a version number rather than a check for a facility (urandom), and that approach can give false positives.)