Steven Zahm@ carolin
re: I noticed there is an upgrade notice on the site where I have CMap installed, but it is not an auto update, as other plugins.
Are you receiving an error when you try to update? If you are, make sure the support license key is activated for it on the Connections : Settings admin page under the Licenses tab.
re: What is the best procedure for handling the new cMap upgrade and not disturb any existing custom CSS related to CMap. I do have all the custom CSS in a Custom.css file.
That depends on where that custom.css file is. If it is in the template’s folder, WordPress will delete it when you install the new version. So you should make a backup of it first. If it is not in the templates folder then it should be fine.
re: I am guessing that any existing custom CSS code will still work , as the code designations would still be the same in the new file version?
In most cases yes, but… the latest version of cMap has many style options it its Template Customizer. These might override your custom CSS.
re: Should the process be to uninstall the existing CMap and then newly install the new CMap file copy that I downloaded manually?
Yes, that will work fine.
Hope that thoroughly answers your questions.