Be aware that it’s possible that some applications are no longer being developed so 64-bit versions will never be available. Then build a plan to upgrade to 64-bit versions of the applications that are critical to you. If you want to be diligent you could review all non-64 bit applications on your Mac and identify the non-Apple applications which you rely on.

Specifically, you’re trying to determine if the developer has a version of that application which’ll be compatible with macOS Catalina (aka macOS 10.15). If you’re opening an application other than Word 2011 when you see this alert, please contact the developer to see if a newer version of the application is available. As you make your plans you should decide if you want to purchase Office outright or via an Office365 subscription.

Flash ahead to June 2019 and Office 2019 is now the current version. At that time, I indicated that it was time to start to plan to upgrade to Office 2016. Microsoft officially stopped supporting and fixing security holes in Office 2011, including Word 2011, in the fall of 2017. Instead, macOS Catalina only supports what we call 64-bit applications. These older applications are what we call 32-bit applications and they will no longer work with macOS Catalina. However, that application will stop working when or if you upgrade your Mac to macOS Catalina (aka macOS 10.15), which’ll be released in the fall of 2019. The application you are opening will continue to work as long as your Mac is running macOS High Sierra (aka macOS 10.13) or macOS Mojave (aka macOS 10.14).

You don’t need to do anything immediately, but you need to put a plan in place. In plain English, this alert is informing you that the particular application that you’re opening, such as Word 2011, is an older application and you need to plan to upgrade to a new version. It also outlines what steps you can take, but let me try to present a clearer explanation. If one clicks the Learn More button, you’re taken to Apple’s article which offers a mildly technical explanation of the situation.

This alert has generated a lot of uncertainty. Microsoft Word 2011 is only one of many applications that can trigger this alert, but Word 2011 is, by far, the most prevalent application that triggers this alert. I’ll explain what this alert means and how you should handle this situation. If you’ve upgraded your Mac to macOS High Sierra or macOS Mojave you have likely seen an alert that looks like the one shown below.

Office 365 on mac high sierra