Upgrading Legacy Custom Templates
If you created custom templates in < 2.0.0, you will need to upgrade theme to work with the new theme structure in 2.0.0.
In version 1.x, the template files were stored like this:
Starting in 2.x, we added support for multiple themes. The template structure now looks like this:
The new theme folders actually have significantly more files, so it is probably wise to start with a copy of our default theme (named "default") and then copy your customized files into the new theme folder.
Other adjustments may be required, but for many themes this will be all that is required.