I have a question regarding creating relationship class for offline data collection. According to this Esri blog, "we recommend that you create relationships using the GlobalID field on your layer so that primary key of the relationship (your parent hydrant feature) is guaranteed to be unique when establishing a connection to a new inspection record."
And then in this ArcGIS Server documentation, it reads, "[r]elationship classes and attachments must use a Global ID primary key."
Also, when I consulted with Esri Support analyst for Collector sync issue I was having, he said the relationship class in my database that did not use Global ID as primary key wasn't causing the issue.
So I am confused whether it's a requirement or a recommendation to use Global ID as primary key, when creating relationship class for offline data collection.