Got an update, how to find patch notes?

[B0WIE]

I don't know if they call them "patch notes" in phones but how do I find out what changes have been made to this phone via the update? With other phones I've usually had an update note page come up, saying whether it's just a security update or if functionality has changed.
Thx.

 

[DominionRoofs]

....

 

[idon12no]

I got the T-Mobile update and it mentioned the standard "security update and improvements" stuff, but I haven't found a changelog anywhere yet