Facebook Reminding Users to Download Messenger

I don't want my messages instantly. I'm on Facebook all the time, but when I go out to clubs, concerts, parties, I do not want to be notified of anything related to Facebook. I keep a strict distance from it outside of my home and office. I also don't want to download another app that slows down my whole phone. I don't even have any games or that much apps. It's the whole "upgrading" BS similar to this that's really killing my phone.