Comment on How to Update WordPress Themes by SEO Dave.
None of the main options from v7 are reused by Stallion Responsive v8*, way too much changed to reuse the v7 options. You can install and activate Stallion Responsive, decide you hate it and switch back to Stallion WordPress SEO v7.* and whatever settings you had for v7 will still be as they were before installing Stallion Responsive.
Basically v8 is a new theme not an upgrade/update.
That being said… Some widget names are the same, this means when switching from v7 to v8 some v7 widgets will still be in the sidebars. Some widgets from v7 no longer exist in v8 (a lot has changed), and some widgets I’ve kept have new features and need to be saved to import the new settings. Any widgets that look broken, go to the widgets page, open the widget up and click Save. Unfortunately WordPress doesn’t have a way to add new features to a widget and automatically add the default widget options, you have to click the Save button to set the new settings.
The Stallion keyphrases, Stallion featured thumbnails added on edit post pages are used by both themes, so if you’ve added a Stallion featured image to all your posts in v7 they will be used by v8, same with the keyphrases.