We didn’t change any functionalities of Simple 301 Redirects actually. Instead, we have revamped the User Interface to provide better user experience for everyone.
Besides, you can check out the changelog and see that we have enhanced our security, fixed the reported bugs by the clients, added import/export feature, improved the overall performance of the plugin by switching to ReactJS.
As the import functionality has been broken on your site. We can’t reproduce the same issue and it is working well on our side. It seems this is a plugin conflict issue. You can do a plugin conflict test.
If still, you are facing the same issue you can contact our support team here.
Thanks!