Old School Meaning

(informal, idiomatic) Characteristic of a style, outlook, or method employed in a former era, remembered either as inferior to the current style, or alternately, remembered nostalgically as superior or preferable to the new style, the older denoting something that would be considered out of date or out of fashion to some, but as such, is considered by others as cool and hip.

Example:   That teacher's old school methods aren't effective, they're just annoying.
  Man, I love that jacket; it's so old school.