outdated

An outdated idea or thing is one that's no longer modern, new, or relevant.

We use "outdated" to describe things like old-fashioned clothes, ancient technology, or ideas from a bygone era. For example, when you see people wearing bell-bottom jeans and flared shirts in an old movie, the fashion might be called outdated now because it doesn't fit with current styles. Similarly, if someone uses a flip phone, which is an old kind of mobile phone, their phone would also be seen as outdated by today's standards. Even ideas can become outdated – something that was once believed to be true or important but no longer holds up in modern society might be considered an outdated concept.