Auto-expanding Archive for E3 O365 accounts

[Mick-C]

I am having difficulty finding the information online that I am after. We have quite a number of shared mailboxes that are reporting "Your archive mailbox is full" and they currently are limited to 50gb. Co-pilot tells me we can simply enable auto-expanding archiving and that this will allow up to 1.5Tb per mailbox of archiving, with no additional cost and that this is available for our normal O365 accounts.

However, it provides me a link referencing Microsoft Purview: Learn about auto-expanding archiving | Microsoft Learn  which I do not believe we are licensed for. So, my questions are:
1. Is auto-expanding archiving available for E3 licenses?
2. And if so, is the overall size limit per account 1.5Tb?
3. Lastly, is there online material that explains this?

[#2]

It is available for E3, but you need to apply the corresponding license to the shared mailbox. Keep in mind that accessing auto-expanding archives in delegate scenarios is not supported, you will have to access the shared mailbox in direct mode (File > Add account in Outlook; Open another mailbox in OWA).
You can ignore the Purview marketing shill in the article above, having E3 is fine.

[#3]

Take a look right here, i believe it can answer your questions:

https://learn.microsoft.com/en-us/office365/servicedescriptions/exchange-online-archiving-service-de...

[#4]

We'll be looking at enabling this in the near future for shared mailboxes. Thanks