Samsung is currently rolling out an update to all Galaxy S8 and Galaxy S8 Plus owners in the United States and Canada that fixes a nasty bug with Samsung's DQA app. Galaxy S8 and Galaxy S8 Plus owners have been reporting a show-stopping issue that force-closes the DQA app every 30 seconds or so, essentially stopping them from using their devices. The app in question is Device Quality Agent, which is used for optimizing Wi-Fi connections. The messages would only let up while the user was not on Wi-Fi, which meant that users who didn't have a way to disable the app and keep it from force closing were unable to use their devices on Wi-Fi.
The fix is being rolled out through the Galaxy Apps store, and should only weigh in at about 943KB, as seen below. Some users are reporting that it's winding up bundled in with other updates, which likely means that users who can't get it through the Galaxy Apps store for whatever reason can always check in the usual place, being the About Device section of the Settings menu. Users who are reporting getting the update aren't noting any sort of issues, and users who had no problems before also seem to be taking the update without any sort of issue.
As with any other update, whether you're getting it through your device's settings menu or through Galaxy Apps, it's wise to make sure you have a good amount of charge in your battery, at least 80%, or plug your phone into the charger. Even with a small update any sort of failure during the flashing process could potentially result in hard bricking the device, which renders it utterly inoperable until the motherboard is rescued with special hardware. The update is reportedly out for all users at this point, so if you're not seeing it, going in and out of airplane mode or rebooting your device may do the trick. If neither of those net you the update and you're still have the DQA force closing issue, you'll likely have to take your phone back to the store you bought it from to have it updated manually.