Taking a U-turn from its previously set April 2026 deadline, tech giant Microsoft has announced a delay in the opt-out phase for businesses to upgrade to the new Outlook, setting the deadline for March 2027. The opt-out phase will also see the email provider’s new version becoming the default experience.
However, entrepreneurs can choose to opt out during this temporary phase, as the bigger headache will be adjusting their businesses to the update rolling out seamlessly.
Stating that the extended deadline will give customers more time, while the Satya Nadella-venture continues to add missing features and various other improvements to the update, Microsoft also noted witnessing “strong and accelerating adoption” of the new Outlook.
“We continue to invest heavily in expanding capabilities and addressing feedback from customers who want to go further with new Outlook,” the company added.
However, when it comes to Microsoft rolling out the new Outlook, things haven’t gone smoothly. In early 2025, the tech venture confirmed that in April 2026, it would begin forcing enterprise users to use the new Outlook, with an opt-out option. The delay now pushes the next deadline to March 2027.
According to the Satya Nadella-led Silicon Valley giant’s original plan, if enterprises opened “Outlook Classic” in April 2026 or later, they would have been automatically upgraded to the new Outlook. This also means the new Outlook would auto-download and open on PCs, but the users still had the option to go back to Outlook Classic.
“Users will be toggled into new Outlook once with this roll-out, with the potential to be toggled again in the future. Users will maintain the ability to go back to and use classic Outlook,” Microsoft previously stated in a roadmap update.
While the new Outlook offers a streamlined, modern user interface characterised by larger icons and increased white space to enhance focus and productivity, it represents a significant shift from the traditional desktop experience. The new version is built on a web-based, cloud-centric architecture that provides superior integration with Microsoft 365 services such as Teams and OneDrive, making it ideal for users who prioritise a unified ecosystem.
In contrast, the classic Outlook remains the preferred choice for power users who rely on its extensive customisation options and ribbon-based toolbars. A critical distinction between the two lies in their extensibility: The classic version supports robust third-party tools such as COM-based extensions and VBA macros, whereas the new Outlook currently offers more limited add-on capabilities, prioritising a cleaner but less flexible environment.
The company claims it is experiencing massive adoption by clients for its new Outlook software. An end-of-support date hasn’t been officially announced for the Classic Outlook, but existing clients can expect support until 2029 at the minimum. New clients can switch to Classic Outlook if they so prefer, but the company is encouraging users to proactively transition as quickly as possible rather than waiting for the deadline.