From olden times; traditional; existing or used since the past (often used in formal/written contexts).
旧来の方法では対応できない問題が増えている。
Problems that cannot be dealt with by traditional methods are increasing.
技術革新により、旧来の常識が変わりつつある。
Due to technological innovation, long-held notions are changing.
旧来の慣習を守る地域も多いが、変化も見られる。
There are many regions that keep traditional customs, but changes can also be seen.