When you access H5 application in Wechat, you will find cache problem preventing you from seeing the latest updates. There are two solutions to clear cache in Wechat.
Solution 1: On the visited page, click the top right menu, click "Refresh". If does not work, close the window and open again.
Solution 2: Click menu "Me" -> "Settings" -> "General" -> "Manage Storage", after run finished, no further action needed, then close your wechat and restart it again. iPhone will not always succeed.