Some examples will be outdated when 0.11 comes out

[Adamkob12]

Hey, I'm reading the book right now and it's awesome!
Just wanted to mention that in 0.11
.add_system(..) and .add_startup_system(..)
will be deprecated in favor of
.add_systems(Update, ..), add_systems(Startup, ..)
There are probably more but these are the main ones.

[PROMETHIA-27]

Cool, thanks for letting me know! I'll try to remember to update them when it releases.