I have turned off all settings for automatic update. I do not want the latest patch that will slow my phone considerably. I have set my phone to block yet I keep getting this message pop up several times a day.
I can't see your photo yet, but if you do the following you will not have the annoying reminder constantly on your Status Bar, but you will still see a reminder when you reboot your phone or pull down the Status Bar.
Go to Settings - Apps & notifications - App info - press the 3 dots - Show System - Software Update - App Notifications - open each of the 4 categories and change the importance to Low and turn all the other sliders off.
Yes I already did as you say. But like you mention, I think dragging down the status bar fires up the spam message. I have turned off everything and then some! Even tried shutting down system apps and blocking notifications on things like xperia assist, update, ect ect.