What are the exact settings which control if the Pages library and Documents library are rendered in Classic or in New experience

Question

I have a team site collection inside my sharepoint online tenant, which i have migrated from sharepoint on-premises 2013. but i am a bit confused on how we can control if our pages library and our document library are rendered in Classic experience or in New experience.

• On the tenant i defined the following:-

• On all the document and pages libraries i have the following setting under Advance settings:-

Now the result i got inside my sites are:-

1. If i access site home page /SitePages/Home.aspx,, which contain a web part for my document library,the home page it will be rendered in classic experience.:-

2. while if i click on the document library itself /Shared Documents/Forms/AllItems.aspx it will be rendered in New experience :-

So not sure why the AllItems.aspx is being rendered in modern experience, while home.aspx is being rendered in classic experience..??

Answer 1

Unless there is some feature enabled on home page that is incompatible with the new UI. It auto-detects when there are unsupported features in place and automatically uses the classic experience even if the setting is for the new experience. Here's an article that details the unsupported features.

https://support.office.com/en-us/article/Differences-between-the-new-document-library-experience-and-classic-mode-30e1aab0-a5cc-4363-b7f2-09e2ae07d4dc?ui=en-US&rs=en-US&ad=US#BKMK_AutoDetectFeatures

Answer 2

Though you have set the default experience as new experience , it will not support for this Document App Part . The settings you have set is only for lists or libraries . You can only display these app part on a modern page .

https://support.office.com/en-us/article/use-the-document-library-web-part-a9dfecc3-2050-4528-9f00-2c5afc5731b0 .