if not when will the updated plugin released
As you know (but to save others looking), upto 2015 is supported in the download section
perhaps some insider can comment or someone here... ArcGIS for AutoCAD
although similar pleas have gone unanswered https://community.esri.com/thread/181354
Yes the current release ArcGIS for AutoCAD 350 does work with AutoCAD 2017 and 2016. However the desktop launcher and the install routine don't recognize the newer versions of AutoCAD. You would have to copy the files from a successful installation of ArcGIS for AutoCAD 350 and NETLOAD the ArcGISforAutoCAD.dll or automate loading using some other technique rather than the desktop .EXE launcher. The next release ArcGIS for AutoCAD 355 will be available very soon.