Answer
To check the server version, make a GET request to:
http://localhost:18681/PCCIS/V1/Service/Current/Info
You can make a get request by navigating to the URL in your browser. The JSON response will have a "pccisVersion" property, which is the version number you are looking for. A similar GET to the following URL will determine the PAS version:
http://localhost:3000/info
The JSON response’s "version" property is what you are looking for. Keep in mind that differing version numbers don’t necessarily indicate a mismatch, as long as the major and minor version numbers sync-up. For example, the PCCIS version 13.5.33.5696 and PAS version 13.5.0000.1816 are from the same release (13.5).