Esri is increasing the pace of releases of ArcGIS for AutoCAD by creating smaller scope releases. This is one of those incremental releases. Be sure to download the newest version of ArcGIS for AutoCAD 355 now, which is available here.
This new release includes updated support for AutoCAD versions 2013-2017 in nine different languages. New in this release is a command to generate local feature classes from all the populated layers in your drawing. This new command is good for creating new local feature classes from well-structured drawings that you intend to share with ArcGIS desktop users, or that you want to add tabular attributes to within AutoCAD.
This important release fixes a bug when connecting to secure services on ArcGIS 10.3.x and higher servers. This release will also warn you when you connect to feature services on 10.3.1 servers containing unsupported date fields. (This issue with feature service date fields in ArcGIS Server was fixed in ArcGIS Server 10.4), but in case you are using 10.3.1 servers with ArcGIS for AutoCAD you will be warned that you cannot synchronize services when a date field is present in feature services on those servers. Check out this brief video for an overview of what’s new in ArcGIS for AutoCAD 355.