Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It
▻https://www.howtogeek.com/129273/why-your-android-phone-isnt-getting-operating-system-updates-and-what-you
Back in the early days of Android, system updates were very random: they would roll out at different times, and often several times per year. Now, Google has taken a much more streamlined approach, releasing one major Android update per year and much smaller, security-focused updates once per month.