Forum Discussion
Classic mode support timeline
There are no plans to remove classic mode anytime soon. For more details, see our post on modern extensibility at http://dev.office.com/blogs/update-on-modern-document-libraries-and-extensiblity Until we roll out the framework and related patterns and practices, we havent earned the right to even talk about it. But since you asked, any change to support would be communicated long in advance.
I know the original post was made in 2016, but doesn't it just show how wrong it is to make a statement like this without the full facts.
You can still use the classic sites in SPO and O365 for the 2019 version and there is no real timeline for when and if they will be depreciated or even removed completely.
Infopath has been depreciated as of writing.
- They are removing the tenant-level classic mode on March 29th - Its downhill from here.
https://techcommunity.microsoft.com/t5/Microsoft-SharePoint-Blog/Delivering-SharePoint-modern-experiences/ba-p/315023
