If you attended the Esri User Conference earlier this month you may have taken the opportunity to fill out an ArcGIS 10.6 readiness assessment to help you identify potential areas for improvement, and options to investigate prior to implementing or upgrading to ArcGIS Enterprise 10.6.
If you weren't able to make it down to the Implementing ArcGIS area of the Esri Showcase and take the assessment with one of our SMEs you can still take it on your own here.
The results of this assessment are based on the high level information you provide and while it doesn't represent the in depth requirements gathering needed for many complex environments it does provide general recommendation and guidance most users will find helpful when planning a migration and it's a great way to start the conversation about upgrading to 10.6 either internally or with your Esri Account Representative.