You Should Upgrade Your Website For these reasons:

Makes it easier for users to share and link to your content with a single URL.
Helps Google’s algorithms accurately index your site.
Requires less resources to maintain multiple pages for the same content.
Reduces the possibility of the common mistakes that affect mobile sites.
Requires no redirection for users, which reduces load time.
Helps Google index more of your site’s content and keep it appropriately fresh.