Hello Gary,
Thank you for writing.
Yes, you are right that color blending is no longer supported. Currently, you have two options:
1. To create several different themes with different predefined colors and user to be able to choose between them.
2. To change the theme at runtime. The following code snippet demonstrates how to iterate through all repositories and how to access some specific style group at run time.
I hope this information helps.
All the best,
Anton
the Telerik team