We've impmented this to automate the updating of basemaps and republishing of a survey: https://community.esri.com/groups/survey123/blog/2017/12/08/an-alternative-way-to-update-the-media-folder-of-a-survey123-form-item
We're having an issue with the tpk basemaps added to the media folder and then republishing the Survey. The entire workflow to build new tpk's, download the existing survey, build a new zip and upload to the form item all works correctly and we can see the form is updated just fine, however the basemaps do not update on the device(s).
Even after deleting and re-downloading the survey item, we don't see updates to the basemaps. The only way we actually see the updates to the basemaps is when the Surve123 app is completely uninstalled and re-installed from the app store. Only then after downloading the survey item again will the basemap changes appear. It's very similar to a browser caching a previous session.
Is there something I'm missing or can look to do?