I don't personally have an issue with loss of access to historic email folders because, like many people, I use an email client and download all messages to my own PC. (Though I am missing 19 June.)
However, I am concerned that when all the online folders are eventually restored the messages may all be flagged as "new" and I unexpectedly receive tens of thousands of "old" emails!
Do we have any reassurance that this will not happen?