Hi @zack and thanks for your query. You are correct that the TX_ code has since been replaced within the Core SDK by the Class StatePaths.
For C++, you would need to use the Stream Engine API (https://developer.tobii.com/consumer-eye-trackers/stream-engine/) which has various parameters exposed such as tobii_get_device_info which can provide eye tracker specific information. The Stream Engine however cannot provide any data regarding Tobii Core Software versions as it operates independently.
If however, you are happy to use .NET then you can download the Core SDK samples available online @ https://github.com/Tobii/CoreSDK
and navigate to Samples -> /States/Interaction_States_102/ which should show you the syntax.
I am not sure if these metrics provide everything you want, so if you could be more specific in your needs, I will do my best to find the requested calls. If you could also elaborate on which SDK you are using, that would be helpful.
Please let us know if we can be of any further assistance.