We are quickly approaching the November 1st deadline when the minimum version requirements for connecting Outlook for Windows to Office 365/Microsoft 365 services will change. So, we thought we’d share more information on why we’re doing that.
After November 1, 2021, only Outlook 2013 Service Pack 1 (with latest fixes) and later will be able to connect to Microsoft 365 services. It’s worth noting here that Outlook 2007, 2010, and Office 2013 versions earlier than 15.0.4971.1000 aren’t supported now, but we know some customers just can’t quit them.
The deadline is approaching!
Since our Message Center post last fall, we’ve seen a drop in the usage of the unsupported versions of Outlook for Windows – great job! If you’re still running older versions, please start working on a plan to move by November 1st.
Our Customer Support team is actively reaching out to tenants that have the most usage on Outlook 2007 and 2010 to help them meet the deadline. If you have questions or concerns about getting all users off these unsupported builds, please reach out to your support teams.
Why are we blocking old versions?
Older versions of Outlook such as Outlook 2007 and 2010 are incompatible with the following upcoming service changes, which is prompting this controlled block:
It can be a challenge to stay current, but there are many reasons why staying current is a good idea:
- Support for basic authentication is ending to increase the security of Microsoft 365 by relying on modern authentication protocols, which are not only more secure, but also provide compliance and policy controls to help you manage your data.
- We’re working on adding support for HTTP/2 in Microsoft 365. HTTP/2 is a full duplex protocol, which decreases latency through header compression and request multiplexing. On the service side, we’ll be able to better prioritize requests and more effectively push data to clients.
- Security fixes will protect your devices against known vulnerabilities.
- Reliability – over the last five years we’ve eliminated 75% of crashes in Outlook!
- Updated versions have all the coolest new features to make your life easier!
- For Office 2007 and 2010, use the roadmaps listed below to move to Microsoft 365 Apps. If your organization is highly regulated or uses devices that can’t take updates, consider Office 2019
- For Office 2013, move to Version 15.0.4971.1000 of Office 2013 (Service Pack 1 with the October 2017 Update)
- For Office 2016, move to Version 16.0.4600.1000 of Office 2016 (With the November 2017 Update, KB 4051890)
- Office 2007 end of support roadmap
- Office 2010 end of support roadmap
- Office versions and connectivity to Office 365 Services (See section specific to Outlook for Windows)
- Deployment guide for Microsoft 365 Apps
Source: New minimum Outlook for Windows version requirements for Microsoft 365