The new policy allows each user to unlock the bootloader of no more than one Xiaomi/Redmi/POCO device per year instead of 3 devices as in the past. Unlike many other restrictions, however, this is a global implementation, not limited to their native Chinese market. Individuals who have already unlocked a device bootloader within the last 12 months will have to wait for their one-year timeframe to expire before they’re able to unlock another one.

Source: Xiaomi Time