[shalmanese]

> I highly doubt that messages are actually being deleted from the system - that's rather an expensive affair and not fashionable from state security point of view.

WeChat, like Whatsapp, stores canonical messages on device and not on the server as opposed to services like Messenger that store messages on the server. It has the same limitations as Whatsapp of only one primary device being able to connect to the service at a time and any new device starting from a blank chat history unless a manual transfer is done.

Some minimal amount of history is stored for government compliance (I believe it's around 30 days but this could have changed) and the government has the ability to flag certain accounts for longer retention but you can be fairly certain that Tencent does not have long term archives of all of your chats, because if they did, they would almost certainly offer chat history across phones.

The disappearance of chats across phones is a major usability pain point of Wechat and something they absolutely would fix if they had the ability but it's a deep technical decision baked in from the early days of the product and the refactor would be non trivial. It also conveniently gets the Chinese government off their back by pointing to a technical reason they can't cooperate to avoid having to deal with the headache of being more deeply enmeshed.