Ios 15.4. 1 is worth updating. After updating the previous version of ios 15.4, the battery life is extremely poor, but this situation has been optimized in the latest version of ios 15.4. 1, which is worth updating. There is also the problem of fluency. After the update, it has been greatly improved and the memory occupation has been optimized.
Ios 15.4. 1 It is not recommended to update the mobile phone. 1. If your mobile phone only has 128GB or only 64GB of memory, it is highly recommended to update it. 2. The most prominent feature of this system is the mask unlocking function, so don't upgrade iPhone 1 1 and below. 3, more is that the hardware of the old mobile phone is not working, so even if it is upgraded, the use effect will be very poor.