1. InfoPath is a dead technology
Microsoft has announced that it will not develop InfoPath any further. It will extend support for current InfoPath products to 2026, but there will be no new features. There are many reasons for this decision, but the main reason is that compared to today’s technology, InfoPath is ancient. The way forms are built and how they are rendered in the browser is not up to date with any of today’s standards. Instead of fixing and patching InfoPath, Microsoft has decided that the best way forward is to abandon it.
2. Functionality will stop working
Although Microsoft is extending support for InfoPath products to 2026, this does not mean that the forms created during that time will work as expected. When development of InfoPath stops, the features will, one by one, slowly stop working, effectively turning InfoPath into abandonware and the existing InfoPath forms into a graveyard of outdated business solutions. For example, InfoPath forms containing custom code effectively stopped working in SharePoint Online (Office 365) in August 2016, turning the Office 365 platform into the largest graveyard of old InfoPath forms. September 2016 PU for SharePoint Server 2010, 2013 and 2016 effectively did the same for SharePoint on-prem installations, where, if Managed Solutions Gallery is used, InfoPath forms with code behind are no longer rendered in the browser. These two examples are the most obvious, but there are many other problems, such as not being able to publish forms from InfoPath 2013 if Outlook 2016 is installed and set as the default browser. Microsoft is not going to fix these problems.