If you upgrade to the v2.0+ of the Pro version then any existing forms will need to be migrated to the new live summary settings. This process happens automatically or can be done manually for each form.

Why this migration?
It is because since Pro v2.0 the fields can be selected and re-ordered with a new drag and drop setting. The usual checkbox that was visible on all fields has been removed in favor of this new setting. Because of this change, some data needs to be re-ordered within the form object. This process takes a few seconds and is without risk of losing any data.
Upgrading from Free or Pro 1.x.x
If you have entered your valid license key (Read here how to activate license) then you should automatically see the update to the new 2.0.x version in your Wordpress dashboard. You may proceed with the upgrade as normal by clicking on ‘update now’.
All Live Summary Pro versions before 2.0 were dependent on the Free version found on wordpress.org. This changes with v2.0. After upgrading, you will notice that the free plugin was automatically disabled. You may safely remove this from your website at this point.
After upgrading, your forms and their summaries will remain working as normal. The migration of each form will happen the first time your form is loaded. You can also do this manually by going into the form settings of your respective form and press the button as seen in the screenshot at the top of this page. After Migrating, the new field selector becomes visible to you and you can start customizing the order of your fields.

What if I don’t do this?
The migration will happen automatically whenever your form(s) load anywhere on your website. This ensures that your summaries remain working even if you don’t perform the migration manually.
What if there are problems after upgrading?
The first thing you can try is resetting the Live summary settings of your form to its default settings. For this you will have to navigate to “reset” tab on the “Live Summary” settings of your form and press the reset settings button. After this, you will have to select the fields you want to see in the general settings of your form.
If there are still problems after that then please reach out through the support form and I will personally assist you further.