Siri stopped working

Which last update are you referring to? 

• iOS Update? Which Version? Update your iPhone, iPad, or iPod touch - Apple Support
• Carrier Update? Contact Carrier. Update your carrier settings on your iPhone or iPad - Apple Support
• App Update? Which App? Contact App Developer? How to contact an app developer - Apple Support

Siri requires internet connection check yours.

For your Internet connection.

• Over Cellular: contact your Carrier (Cellular Service Provider). The agency who issued the SIM to you
• Over WiFI: Contact your ISP (Internet Service Provider), the agency who provided the Internet Service on your Modem/Router to you

You may also go through this article to troubleshoot --> If Siri or "Hey Siri" isn't working - Apple Support