According to the update notice, the covid-19 new coronavirus exposure notification function is added in IOS 13.7, which supports new mimetic emoticon stickers, shares icloud folder from file app, and contains error repair and improvement. < / P > < p > considering that it is likely to be the ultimate version of IOS 13, foreigners specially find out iPhone se, iPhone 6S, iPhone 7 and iPhone XR, and try to compare them with the previous IOS 13.6.1 after upgrading, mainly examining the system fluency, switching speed and performance score. < / P > < p > in general, the four models mentioned above have almost no difference in running speed and running points before and after upgrading, that is, there is no reactive power. Considering the bug repair of IOS 13.7, users are advised to update with confidence, including those who use the old IOS devices mentioned above. American companies begin to give up R & D: who should pay for corporate research?