new wine in an old bottle

• new wine in an old wineskin

From Matthew 9:17 of the King James Bible. "Neither do men put new wine into old bottles; else the bottles break, and the wine runeth out, and the bottles perish; but they put new wine into new bottles, and both are preserved."

new wine in an old bottle (plural new wine in old bottles)

1. (idiomatic) A significant change introduced to an entrenched system or method.
2. (idiomatic) A new thing passed off as old.

• old wine in a new bottle