A msz flashed that a critical update is ready to download for slow ring insiders but I'm using w8.1

[Jaswindder g]

Today in my L520 a critical update has flashed via slow ring insider. I'm using wp8.1 and not in interested in w10 because of its bugs. It was also downloaded and installed automatically. After update my L520 is on denim as past. To stop as insider what to do, i have downloaded "windows insider" aap, can i solve my issue by deleting this app. Or i should i have to continue as slow ring insider.