PageLines 2.0 is a major new release to the previous Platform Pro product. When upgrading from Platform Pro there are some things to consider.
Always back up your database before doing an upgrade
In 2.0, there is no longer a Base child theme that handles custom code. Instead, use the PageLines Customize Plugin
All data will be untouched, your posts, pages and content will all remain intact in the database.
Default option settings have changed in 2.0 so any default options set in Platform Pro will be removed in the upgrade
Section control has changed in 2.0 to be more flexible and as a result these settings will need to be reset after the upgrade
PageLines 2.0 has been upgraded to incorporate HTML 5 and some of the html structure has changed. Sites with heavy CSS customizations will need to make changes to their CSS after the move.