Alternatively, you can download the patch manually for the old systems and install it on this link you can see the information about this patch. Even if you installed the vulnerabilities protections you need to change your behavior regarding emails and files you receive.
We have observed a massive peak in WanaCrypt0r 2.0 (aka WCry) ransomware attacks today, with more than 57,000 detections, so far.[…] Avast detects all known versions of WanaCrypt0r 2.0, but we strongly recommend all Windows users fully update their system with the latest available patches. We will continue to monitor this outbreak and update this blog post when we have further updates.