TomCat runs on Java. To find the Tomcat version, you have to find were Java is installed. This can be anywhere.

For me, the location is:

C:\Program Files\HelpSystems\GoAnywhere\jre\bin

So open cmd and change to the location:

cd "C:\Program Files\HelpSystems\GoAnywhere\jre\bin"

Find the Java version:

java -version

I get:

openjdk version "1.8.0_192"
OpenJDK Runtime Environment (Zulu 8.33.0.1-win64) (build 1.8.0_192-b01)
OpenJDK 64-Bit Server VM (Zulu 8.33.0.1-win64) (build 25.192-b01, mixed mode)

To find the TomCat version:

java -cp "C:\Program Files\HelpSystems\GoAnywhere\tomcat\lib\catalina.jar" org.apache.catalina.util.ServerInfo

I get:

Server version: Apache Tomcat/7.0.105
Server built:   Jul 2 2020 12:25:26 UTC
Server number:  7.0.105.0
OS Name:        Windows Server 2016
OS Version:     10.0
Architecture:   amd64
JVM Version:    1.8.0_192-b01
JVM Vendor:     Azul Systems, Inc.