[err_assertion]: path (string) is required in restify 8.5.1 version

[SreekanthOAuth]

Current version: 6.3.4

We are using the below router to serve the index.html

server.get(/\/?.*/, restify.plugins.serveStatic({
    directory: path.join(__dirname, '../build'),
    default: 'index.html'
})
);

And we are planning to migrate to 8.5.1 version and getting [err_assertion]: path (string) is a required exception.

Would be a great help if you guys can share about the replacement for this.

Thanks,
Sreekanth