Qq shows the update log and the time of disappearance.

Will not disappear. Theoretically, it will be kept forever, as long as your QQ is valid. Moreover, the log does not violate any rules, or has offensive language and remarks that violate the law. It will basically not disappear. QQ, short for Tencent QQ, is an Internet-based instant messaging (IM) software developed by Tencent.