Microsoft Office Add-Ins And Internet Explorer 11
As you may be aware from the global celebrations, Microsoft brought Internet Explorer 11 to the end of its life on June 15th 2022. Well, sort of. There are exceptions, and if you have an MS Office Add-In, Internet Explorer’s end-of-life is not necessarily its true end.
Why Are Add-Ins and Internet Explorer Linked?
Microsoft Office Add-Ins are actually web sites with access to a specific officejs Javascript library. They are registered with Office using a manifest XML file and executed inside a frame in Office. As an Add-In is a web site, it requires a web browser to run, and this is where it gets complicated.
The following table helps you understand which browser is used to run MS Office Add-Ins:
| Operating System | MS Office Version | Browser |
| Office On The Web | Whatever browser you are running in | |
| MacOS | Any | Safari |
| iOS | Any | Safari |
| Android | Any | Chrome |
| Windows 7+ | Office Standalone 2013 – 2019 (i.e. not Microsoft 365 subscription) | Internet Explorer 11 |
| Windows 10+ | Office Standalone 2021 (i.e. not Microsoft 365 subscription) | Edge |
| Windows 7, 8, 10 (< v1903) | Microsoft 365 Subscription | Internet Explorer 11 |
| Windows 10 (> v1903), 11 | Microsoft 365 Subscription < 16.0.11629 | Internet Explorer 11 |
| Windows 10 (> v1903), 11 | Microsoft 365 Subscription >= 16.0.11629 | Edge |
You can find the full table of browsers used by MS Office Add Ins on Microsoft’s page. However, from this snippet, you can see that, in some circumstances, Add-Ins use Internet Explorer to render.
Fortunately, at the same time that Microsoft end-of-lifed Internet Explorer 11, they also altered their AppSource (the app store for Microsoft Office Add-Ins) certification policies so that your Add-In no longer has to function with Internet Explorer for approval in the store. Microsoft asks (but does not require) that you at least get your Add-In to output a graceful failure message if it detects that it is running in Internet Explorer 11.
From a practical point of view, you should still consider supporting Internet Explorer 11. We typically still support this for our Add-Ins using a combination of shims, Babel and hand-coded workarounds. The reason for continuing to support it is that many users will still use off-the-shelf Microsoft Office rather than Microsoft 365 Office and so will see Add-Ins presented by Internet Explorer 11. We also recommend a graceful fallback approach where some features of your Add-In may not be available in Internet Explorer 11, even if the core functionality still works.
To read our previous update on MS Office Add-Ins and WOPI, please take a look at our blog. If you are interested in working with McKenna Consultants to create or maintain your Microsoft Office Add-In, please get in touch with our team today.
