Both Uses

obsolete
in
Major Barbara
(Auto-generated)

Across the crest runs a platform of concrete, with a parapet which suggests a fortification, because there is a huge cannon of the obsolete Woolwich Infant pattern peering across it at the town.†
Act 3

obsolete = no longer in general use because it was replaced by something better
It scraps its obsolete steam engines and dynamos; but it won't scrap its old prejudices and its old moralities and its old religions and its old political constitutions.†
Act 3 *

Definitions:

(1) (obsolete)
no longer in general use because it was replaced by something better
(2) (meaning too rare to warrant focus)