I would like to know if SMI-S is still supported in the latest XMS versions.
Yes our latest 6.x XMS does support SMI-S.
I have observed that the latest copies of the XtremIO Storage Array User Guide no longer contains the appendix covering "Configuring the SMI-S". I am working on a request to address that.
There was an issue with SMI-S support in early release of 6.x XMS but was addressed as of 6.2.0-81. For reference view our release notes.https://support.emc.com/docu95191_XtremIO-Management-Server-(XMS)-6.2.2-3-Release-Notes.pdf?language...
With target code for either X1 or X2 arrays we are recommending XMS code level higher than where the patch was implemented. As such you should be able to enable and utilize this feature. If you should encounter any issues, please open a service request with support to analyze further.