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Office 365 – 300 Days of Mainstream Support Left for Outlook 2010

Let’s pause for a minute and mark October 13, 2015 on our calendars; this is the final day of mainstream support for Outlook 2010.
This is especially relevant to Exchange Online users as the system requirements for Office 365 state that it is designed to work with “any version of Microsoft Office in mainstream support”. While Microsoft does not actively block you from connecting to Office 365 with legacy versions or client applications, the text around older versions includes phrases like “does not recommend”, “limited support” and “quality of user experience will diminish over time”.
The “evergreen” nature of Office 365 means that the “server-side” of the service architecture is always being updated and improved; in some cases, these new features are only available to users running the most current client applications.
Knowing that we have 300 days to plan and execute the upgrade of our Outlook 2010 installations, below are some options that are available to us.

Office 365 ProPlus

For Office 365 users with E3 or E4 licensing, you’re already licensed for the latest version of Outlook via Office 365 ProPlus. Even if you’re not an Office 365 customer today, Office 365 ProPlus is available as an individual SKU and it has a number of benefits over traditional Microsoft Office licensing.
If you’re not familiar with Office 365 ProPlus, it’s essentially a subscription-based version of Microsoft Office that is tied to your Office 365 user account. Occasionally there is confusion that this product is a “web-based” version of Microsoft Office which is not the case, it’s installed locally on the PC and can be run while disconnected from the Internet.
Office 365 ProPlus uses the “Click-to-Run” deployment process for installation and updates which means you can start using it within minutes of launching the installation and it’s always kept current in the background. Users can install it themselves directly from the Office 365 portal on up to 5 machines or you can manage the installation using the “Office Deployment Tool” which allows for additional customizations.
Microsoft has some pretty thorough documentation on deploying Office 365 ProPlus. I would start by checking out this deployment guide: Getting Started Guide for Deploying Office 365 ProPlus. There is also a video series up on Channel9 that covers the many aspects of upgrading your Office deployment: Office 365 ProPlus Deployment for IT Pros. If you work in an environment with a lot of Office “add-ins” or complex documents, you may want to consider using “Office Telemetry” to assist with your upgrade.

Office Professional 2013

The traditional MSI installation of Office Professional 2013 is still available and it’s possible your organization is already licensed for it through an agreement with Microsoft. Having worked with the Office 365 ProPlus process for a while now, this installation method seems quite archaic; however, if your organization is licensed and setup to deploy Office in this manner, it probably makes sense. The use of “Office Telemetry” is also an option here for assisting with your deployment.
One thing to watch for here is that this installation method only allows for one version of Outlook to be installed on the PC at a time. Additionally, Office Professional 2013 includes the Lync 2013 client which may be important if you currently have the Lync 2010 client in use.

“Gemini” / “Office 16” / “Office 2016”?

This is where we diverge into rumors and speculation. Most expect Microsoft to release a new version of Microsoft Office in 2015. Perhaps sometime in the second half and possibly in coordination with new releases of Exchange and Lync. It’s conceivable that there may be more known or even an announcement around the time that the Ignite conference occurs in early May 2015.
That said, it’s hard to do any planning around a product without a name or timeline and where every description includes the words “perhaps”, “possibly” and “conceivable”.


  • October 13, 2015 is the last day of mainstream support, extended support will continue until 2020
  • Office 365 clients with E3/E4 are already licensed for Office 365 ProPlus
  • Office 365 ProPlus can be installed by users or managed using the “Office Deployment Tool”
  • Office 365 ProPlus may be a viable option even if you’re not an Office 365 customer today
  • Office Telemetry can be a useful tool for deployments in complex environments

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Joe Palarchio

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