The Office 365 E5 plan, which Microsoft announced in July, will be available to customers starting December 1.

The E5 SKU is listed on the Volume Licensing price list preview which Microsoft published on November 1. The Office 365 E5 SKU will be replacing the current E4 version.

The Office 365 E5 SKU will include Skype for Business (Lync) with support for features including Cloud PBX and Meeting Broadcast; new analytics features, like Power BI Pro and Delve Organizational Analytics; and new advanced security features, such as eDiscovery, Customer Lockbox, Data Loss Protection (DLP) and Safe Attachments. (Note: DLP is already in existing Office 365 E3 plans, Microsoft officials clarified.)

"With E5, we have expanded our market opportunity for Office 365 by more than $50 billion. This new E5 SKU and the launch of Office 2016 will drive one of the biggest new businesses for us," claimed Microsoft CEO Satya Nadella during Microsoft's July earnings call.

Microsoft isn't yet releasing the per-user price of Office 365 E5, a spokesperson told me when I asked. The plan is for Microsoft to make that price available on December 1.

Office 365 E4 sells for $22 per user per month, or $264 per user, per year. E4 includes Skype for Business with Enterprise Voice and unified messaging; the full suite of locally downloadable Office apps; and Power BI for Office 365 (which is being superseded by Power BI pro).

One of my contacts with licensing expertise speculated that E5 could go for $20 to $40 total per user per year more than Office 365 E4.

According to information Microsoft officials shared in July, E4 will be retired when E5 becomes available.

Net new customers will be able to purchase E5 or any combination of E1 and E3 with available upgrades to obtain Cloud PBX and PSTN capabilities. Existing E4 customers will have step up options to either E5 or E3 plus Cloud PBX. Customers who wish to maintain their licensing position, will be able to renew into E3 and Skype for Business Plus client-access license (CAL).

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Existing Office 365 customers will be able to upgrade to E5 via step-up SKUs that charge the difference between what the customer currently has and E5 as the step-up price to E5. Add-on SKUs will also be available with customers who are maintaining on-premises licenses with Software Assurance.

In July, Microsoft announced previews of three new Skype for Business services that will be part of Office 365 E5: Skype Meeting Broadcast; PSTN Conferencing and Calling; and Cloud PBX. In October, Microsoft broadened availability of all three previews.

Skype Meeting Broadcast enables users to broadcast of a Skype for Business meeting on the Internet to up to 10,000 people, who can attend in a browser.The Cloud PBX with PSTN Calling service provides users with the ability to make and receive traditional phone calls in their Skype for Business client, and to manage these calls using hold, resume, forward and transfer.

Microsoft officials said Cloud PBX will be generally available worldwide before the end of this year. PSTN Calling and PSTN Conferencing will be available in the pre-release markets where they're being tested before the end of this year.

Microsoft has more than 60 million active monthly users of Office 365 commercial(meaning business) users as of October 2015, officials said. Last quarter, that number was 50 million, according to Microsoft.

Update (November 4): Office 365 E4 will remain on the price list till June 30th, 2016, Microsoft officials said.