Task: after_update_code is deprecated ... what is the new way of writing this

So, I use this as my current after_update

task :after_update_code, :roles => :app do
    do_something
end

But when deploying, I get this error message

 before_ and after_ is deprecated, please see the new before() and after() methods

I looked and tried to write this

after :update_code, :roles => app do
    do_something
end

but Capistrano simply ignored him. What is the correct way to upgrade?