Use ArcGIS Server? Want to edit data out in the field with disconnected editing capability but don’t want to be forced into the ArcGIS named user model just to use Collector? Webmapsolutions.com might have an answer for you! They have built an offline-enabled ArcGIS data collection app which works with ArcGIS Server (no named user required), but can also work with Portal and ArcGIS Online! Check it out.