Different Launch Events

I have an application that we have converted to xpages using the xpage framework.

However the framework specifies to open an xpage launch in the notes client (which is fine for 8.5.1 clients) however we are looking for a way to open a specified navigator if the client is using 8.5 or older. Is this a possibility or no.

Ideally we want everyone on 8.5.1 but that won’t happen.

Any help appreciated.