Can we change jcr:primaryType of the node after it is created

Yes, you can change folder from code by giving same name to the folder, just change  jcr:primaryType="sling:Folder"

<?xml version="1.0" encoding="UTF-8"?>
<jcr:root xmlns:sling="http://sling.apache.org/jcr/sling/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0"
    jcr:primaryType="sling:Folder"
    jcr:title="test folder project"
    sling:resourceType="sling:Folder"/>

in filter.xml, you can update

<filter root="/<foolder-destination>/testfolder" mode="update"/>

 earlier testfolder was "nt:folder" now updated to sling:Folder

Thanks

jcr:primaryType is a protected property and can not be changed or removed by the application using the API. Please refer this document for more details :

https://developer.adobe.com/experience-manager/reference-materials/spec/jcr/1.0/6.7.5_Special_Properties_jcr_primaryType_and_jcr_mixinTypes.html

You can restructure the old folders with Sling:Folder as jcr:primaryType using some script and update existing BE logic to create the folder as sling:Folder.

Goto folder properties and change it to "orderable". this will change the the primaryType from nt:folder to sling:orderedFolder. you can uncheck this again to the make primaryType to sling:folder

YES! it is posible and i have it working correctly.

It is the same code that is used by the POST servlet when you want to change the folder properties using the UI

Node folderNode = folderResource.adaptTo(Node.class);
folderNode.setPrimaryType("sling:OrderedFolder");
folderNode.getSession().save();

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