Was that in the app its self? Because one of the things they told me to do after an update was to clear the cache partition in recover mode.
Turn phone off
Then hold the power-volume up-home
The phone will go into recovery mode
Then use the volume down to highlight clear cache partition Press power
Then volume down to say yes and press power again
The phone will then reboot in recovery mode then press power to reboot the phone
This will clear out all the old files that are left behind after an update
It will not change any of your settings on the phone
This partition is like a hard drive on a computer and holds all the old files
that your phone doesn't need anymore and some of these files can cause
conflicts with the new files but it is safe to clear this out after you get an update
Also have you gone to the play store and update all your apps?
Going from nougat to oreo they may all need to be updated