In previous version of Ignition 8, when editing the value property of a memory tag of data type document, I believe you used to be able to right click on the base object and change it to an array. In version 8.0.13 on, I’m not seeing this ability. The “change to” option is greyed out:
Was this changed intentionally? I noticed that if you export the tag and modify the JSON so that the value is an array, then reimport the tag, Ignition seems to handle the base structure being an array just fine: