Back in February of this year, Microsoft officially announced that it would be ending “mainstream support” for Office For Mac 2011.
Even then, Microsoft had a firm date in place: October 10, 2017. Now that the big day has arrived, Microsoft has indeed fully ended support for the software. It has been almost seven years since the software initially launched, so it certainly had a lengthy run. Of course, Microsoft has always promoted other Office products, including Office 365 ProPlus and Office 2016 for Mac, as worthy replacements.
As far as what Microsoft means by mainstream support, it means that the applications packaged within Office For Mac 2011 (Word, PowerPoint, Excel, and Outlook) will no longer receive any kind of updates, including security or features. On top of that, any and all technical support for the software is also seeing its final sunset.
It’s worth noting that Microsoft Lync for Mac 2011 has an expanded support period, which will be running until October 9, 2018.
Microsoft has made a point to say that it has not even tested the 2011 suite with current Mac software, including macOS High Sierra. It is possible that it still works in some capacity, but with no feature or security updates planned, it might be best to upgrade to the newer suite of apps.
As noted above, Microsoft recommends that Office users switch to the newest installments of the software at their earliest convenience. The newest options are supported on macOS 10.10 or later, including the newest release, macOS High Sierra.
How often do you use Microsoft Office products?[via MacRumors; Microsoft]