FYI, ArcGIS Enterprise 10.5.1 is now available. Learn about its new capabilities in this blog,
What’s new in ArcGIS Enterprise 10.5.1 | ArcGIS Blog
and the ArcGIS Enterprise 10.5.1 Functionality Matrix whitepaper is also available,
http://www.esri.com/library/brochures/pdfs/arcgis-enterprise-functionality-matrix.pdf
Hope this helps,