I have just upgraded from Roots Magic 6 to version 8. Version 6 allowed me to generate HTML files and save them in a folder on my computer. Roots Magic 8 does not appear to have that same option. Instead, it directs my files to MyRootsMagic, Ancestry TreeShare, or FamilySearch Central.
“We don’t currently have plans to support the RM6 or older style HTML websites. The old style websites were deprecated in RM7 and not continued in RM8. The only websites we offer are the MyRootsMagic websites that we host.”
When you need to update your website you can still use RM6 to generate your HTML files. In RM8 create a GEDCOM (File, Export Data) and then import it back into RM6 to make them.