It does not update automatically but, if your Search Head can reach
splunkbase.splunk.com and you have not turned off the feature, you should see the
[update] strings in the app pane for this (and any other) app after a new version is released. Your users will generally let you know soon enough after this happens so don't worry about watching for it.
Do you mean when new Analytic stories published in newer version of ESCU app, you want to pull those Analytic stories automatically ? In this you need to upgrade the ESCU app which will have new content, there are no such automatic way in ESCU app or inbuilt in splunk.