Prudence 2018 was a theme released in January 2018 as a part of Aurora Update 11. Similar to Hale 2015, Prudence 2018 adapted the Prudence design and kept the powerful features of Sherman. A child of the Cornerstone theme, Prudence 2018 will continue to benefit from all new features added to Aurora for years to come.
So what's different if you're converting a Hale or Prudence site to Sherman, Hale 2015, or Prudence 2018? Here's a few quick points:
The Primary Navigation menu needs to be set in Appearance > Menu; in Hale there was an option to set it in Appearance > Customize.
If you had pages built with Bootstrap, you'll have to redo them because the new themes use Bootstrap 3.
User Profile Pages will need to have their page template reassigned. Go to pages, and use the checkboxes and the Bulk Action > Edit feature to do many of them at once.
Hale 2015 was a theme released in August 2015 as a part of Aurora Update 9. The bold blue Sherman theme was released in the summer of 2014, and its advanced features and customization options proved very popular. However, a number of customers requested a theme with all the functionality of Sherman but with the softer tones of the original Hale theme that was released in 2013. Hale 2015 addresses this issue, adapting the popular Hale design and keeping the powerful features of Sherman. A child of the Cornerstone theme, Hale 2015 will continue to benefit from all new features added to Aurora for years to come.