刻舟求剑 | kè zhōu qiú jiàn
Xi Jinping used this chengyu in an article on improving education in political philosophy on August 31st, 2020.
Meaning
Lit. a notch on the side of a boat to locate a sword dropped overboard (idiom); fig. an action made pointless by changed circumstances
Original
“我们通过守正创新形成了中国特色社会主义理论体系，守正就不能偏离马克思主义、社会主义，但不是刻舟求剑，还要往前发展、与时俱进，否则就是僵化的、陈旧的、过时的。”