musya alr, spam&scam detection is a fair point,
And RCS is not? Are people still using unencrypted, plain-text SMS (which is also limited in any possible way, starting with inability to even attach a single image)?
JohnnyBravado There is a very good reason not to upgrade for a while.
You need to be on Android 8.0 or lower for that, as the main mechanism for that sideloading lock is Google Play Services. Android version has nothing to do with that as long as Google Play Services is still supporting it.
Edit: Sorry, Android 7.0

So if you’re on Android 6.0.1 or lower you have nothing to worry about and it won’t affect you.