Create Package Installation Data for Themes1 user found helpful
since version 8 i am helpless to create the installation data for content swap (content.xml + content files).
Andrew has created a addon that was perfectly working on 5.7:
The add-on is using the Core class Concrete\Core\Backup\ContentExporter for creating the installation data. But since 8 the methods are deprecated and when i try to create content swap data i get the error message "Please use the migration tool". But where i can find the Migration tool? Does it have the same possibilities? Or do i have to develop themes on 5.7 if i want to create sample data?
For my new theme package I had to create my package for 5.7.5+, not 126.96.36.199, and test, then use the 'sample_content-generator' for 5.7.
My new theme package with xml, etc worked ok for 188.8.131.52.
Hope that helps.
Here is a link to the migration tool.