https://www.flyingblue.com/en/news/extend-your-flyingblue-miles
旧制：
Flight activities extend all of your Miles for 2 years.
Commercial activities extend only the Miles earned from Flying Blue partners for
2 years
新制：
Any activity (flight or commercial) will extend all Miles for 24 Months.
高卡、联名卡、FB Extra订阅维持永久效期