Your phone reports it has been updated and when you check, YES, there it is, the latest security date shows in About Phone.
However, some naughty manufacturers will update the security date on a phone but not actually install any patches - according to some German researchers reported in a UK paper.
Most are not that bad, but still miss out some of Google's patches when they provide a security update.
They report the following number of Google issued patches typically NOT installed by the manufacturer when they show a security update:
0 - 1: Google, Sony and Samsung
1 - 3: OnePlus and Nokia
3 - 4: HTC, Huawei, LG and Motorola
> 4: TCL and ZTE
All - some naughty NAUGHTY companies that they don't list.
Hmmm, I'm surprised Google allows this. Well, I'm not actually.
