About some iOS 9 users can't update WeChat solution
About section iOS 9 users cannot update WeChat
Section iOS 9 users may not be able to install and update WeChat through AppStore, which can be solved by:
Method 1: Upgrade to iOS 10 (iPhone 4S or higher)
Method 2: Find the WeChat installation by using "I" -> "Purchased Items" in the upper right corner of the AppStore.