Collector for ArcGIS v10.4.1 (Android) released on the evening of January 12th into both Google Play and the Amazon App Store. It includes a series of stability improvements as well as minor enhancements like integration with the recently released Android version of Navigator for ArcGIS and the soon to be released Android version of Workforce for ArcGIS.
You can find additional details about the release in the What's New topic on the Collector documentation site.
