My understanding is MLTK is an out of the box app. In that case if my Splunk instance is upgraded, will the oob apps (MLTK) will get upgraded automatically too ? Or we need to manually update to latest version from Splunkbase like other apps ?
MLTK is not an out-of-the-box app. It must be upgraded separately, but does not necessarily need to be upgraded when Splunk Enterprise is upgraded.