v4.0.0

Breaking

• Rename the http option to onlyHttps.
  Previously, the default behavior was to use DNS, and if that failed, the request would fail. What's changed is that by default it will now try DNS, and if that fails, it will fall back to HTTPS. The option was renamed to better reflect that HTTPS is used even when {onlyHttps: false}.

Enhancements

• Add built-in fallbacks for DNS and HTTP checks (#34) fdcbb7d
• Add fallbackUrls option to enable users to add additional HTTP fallbacks (#34) fdcbb7d

v3.2.0...v4.0.0