The popular messaging app WhatsApp still utilizes the method of locally storing chat records. Although the official backup method is given, it is currently unable to synchronize between iOS and Android devices.
A few days ago, WhatsApp is officially developing a cross-platform chat history migration feature. The information page is online, but it is unavailable.
WeChat currently also utilizes local storage to save user chat records, but it has developed a cross-platform chat record migration function.
Android users can use it in “Settings” -> “Chat” -> “Chat History Backup and Migration”, and iOS users can use “Settings” -> “General” -> “Chat History Backup and Migration”.
(Source)
