How to determine the version of the twbx file?

[pjcpjc]

Is there anything in a .twbx file to determine which version it is? I'm working on a system whereby the .twbx gets deployed in a cloud environment and the .twbx file needs to be "saved as" an older version of tableau in order to run online.
I don't think tableaudocumentapi could be helpful in terms of being able to change the "saved as" version of the file, but it would be nice if my tableaudocumentapi script could at least print out some diagnostic information in case the deployment engineer forgot to perform this step.

[pjcpjc]

Not sure how active this repo is, but @RussTheAerialist appears to responding to things....

[jacalata]

You're right that we couldn't do the actual upgrade, but version info is in the twbx and we could make it available through this

It's an attribute on the workbook element:
workbook source-build='9.3.0 (9300.16.0315.0125)' source-platform='win' version='9.3' xml:base='https://tableau.laatgetallenspreken.nl' xmlns:user='http://www.tableausoftware.com/xml/user'