Indicators have always updated themselves on the fly, live, you’ll notice that looking at charts, especially on lower TFs, but you could only access them on closure of each bar.
Now you can access them while higher TFs are forming, this is by default. UPDATEONCLOSE will change this setting letting you access only values at the time of the last closed bar.
So referencing an MA on a daily chart from a 1-hour TF will return 24 different values. With UPDATEONCLOSE one value will be returned 24 times, that of the last close.
