Samsung had been rumored to be preparing a February security patch for the Galaxy S8, sparking speculation that it would also come with the official update to Android 9.0 (Pie) for the 2017 flagship. This patch is now reportedly arriving on the devices in question, but it is still based on Oreo. Therefore, fans of this phone still have another month to wait for their major OS upgrade.
https://www.notebookcheck.net/Samsung-Galaxy-S8-series-will-get-new-security-patch-this-month-but-no-major-OS-updates.407186.0.html
3/31/19 - Current update ran during night. Did this update make some changes to home screen icons (i.e. phone, camera, contacts...) and appearances to some screens?