Most Android phones are still running older versions.
Even though Android 16 Beta 4 just launched for Pixel testers and Android 15 is rolling out to Samsung devices running One UI 7, most Android users are still running much older software like Android 14, 13, or even earlier.

Google no longer regularly shares Android version stats, but thanks to data discovered in Android Studio, we now have a fresh perspective. Android 14 has seen significant growth since July, while Android 15 – despite being released months ago – has yet to reach even 5% of devices.
Source: androidauthority