Context: We released a new Theme Library in October 2016. This is a collection of professionally designed page layouts that can be used as course landing pages. More info here
Installing one of the layouts from the Theme Library will not affect a previously active/customized theme. The new layout will be installed into the Course Landing Page Layouts folder of the active theme. So you can continue using the older layouts for some of your courses if you choose to.
That said, some of the snippets are different between the old and new layouts. For example, if you've customized the "course_landing_page_action_buttons" snippet, these changes will not be reflected in the new Mountain layout. This is because Mountain uses the snippet "mountain-1-6-1v1-0-0_course_landing_page_action_buttons" instead.
You'll be able to customize these new snippets in your theme once the layout has been installed.
@Jill Morton - This should answer your questions from this thread: http://help.thinkific.com/discussions/topics/313929. Just to be clear - this means that you will need to recustomize the "Free Trial" button if you switch to one of the new landing page layouts from the Theme Library.
I have some courses in Thinkific already. I want to "Upgrade" them 1 course at a time. Is it possible to create a "New" blank course in one of the New templates and copy over the course without losing the original course?
If you're looking to switch a course to a different theme, you can do this at anytime and can switch back as well. The actual course content will not be affected. This only changes the design of the course landing page. This is if you are still staying within V1 themes.
If you're thinking about upgrading to V2 themes, this will affect your entire site (all pages and course landing pages). You can take a look at this article for more info: http://help.thinkific.com/support/solutions/articles/224819-upgrading-to-the-updated-page-builder
Do the landing themes really cost upward of $5000 to use or is that just demo text?
Currently, all the themes are free. The demo is showing what the buy button would look like when set a price on your course.