[Q] Software upgrade??? topic

I was in the car and I needed to hurry up, and when I unlocked my screen a window popped up, having the title "Software Upgrade" and when I read it, it said "Your software needs to be upgraded in 30 days. Upgrade it now or after 30 days has passed" and I had the choice of picking Cancel or Upgrade, but as I was hurrying up, I chose "Cancel" and now I don't know if it was an application that had to be upgraded or my phone's system??? The apps I am using are WhatsApp and Viber, did the message come from one of them? I can't believe now that I canceled it..