Fired up Quicken and it immediately updated to 59.18. I really wish Quicken would provide some kind or confirmation box to accept or defer the update. Along with this box, a link to the readme that explains what the update contains.
Once it completes, you can review the release notes to discover this is supposed to fix issues with the online backup. Since I don't use it, there was really no need to force me to update. Just sayin'.
Having said that, the update completed successfully and my Quicken seems to be running OK. No issues with OSU, backup reminders, or other widely reported issues.