Just to clarify, this is iOS only. On Android, the client can export plaintext messages to storage, or you can use something like Titanium Backup, which wraps

Just to clarify, this is iOS only. On Android, the client can export plaintext messages to storage, or you can use something like Titanium Backup, which wraps up the app installer AND data directories in a tarball and can restore it across other many different versions of Android.