Previously, the Collector app required an organizational account on ArcGIS Online. I have one of these, but only have a single named user. With the addition of Portal for Arc Server, does this requirement go away? My understanding of Portal is that it is like an on premises ArcGIS Online. Can anyone shed some light on whether I will be able to make use of Collector for my 2 field staff members without having to buy a 5 pack of named users? I am part of a GIS consortium with ArcGIS Server Enterprise. Thanks!
Collector requires an ArcGIS organizational account, and those actually include organizations on ArcGIS Online, as well as Portal for ArcGIS accounts. So you can use Collector with Portal for ArcGIS accounts.
At 10.3 your ArcGIS Server license comes with Portal including at least a 5 named users (for Standard ... more for Professional).
Portal with your named users can be used to drive Collector.
See this blog post for additional information: What's new in ArcGIS 10.3 for Server | ArcGIS Blog