jiù​píng​zhuāng​xīn​jiǔ

new wine

旧瓶装新酒 (舊瓶裝新酒) jiù​píng​zhuāng​xīn​jiǔ
new wine
new concepts or content presented in an old framework; literally "new wine in old bottles" (an idiom based on Matthew 9:17, though in Chinese it typically describes the practice of using old forms for new content rather than warning against it)

Frequency

Written text
0.071 per million

Sources

Definitions
CC-CEDICT
Frequency data
BCC Corpus (BLCU)