I have updated Nintex Form from version 2.3.31 to 2.11.5 directly. Now I am getting an error when opening a registration page with NintexForm, "Object reference not set to an instance of an object."
When I remove and added List Form web part back on the page, it started function as expected. My problem is that I have more than 50 web pages to be replaced. So I think the old ListForm webpart is nomore functioning as it should. Is there alternative way to update the oldwebpart so that I can avoid manual replace process.
This seems to be something that @nintexsupport need to help you with. You can send them an email at email@example.com and explain all of this to them.
Sure they will be able to assist.