ExtremeXOS 31.7 is compatible with the version of Extreme Management Center or ExtremeCloud IQ - Site Engine shown in this table: http://emc.extremenetworks.com/content/common/releasenotes/extended_firmware_support.htm
Switch Engine 31.7 is compatible with ExtremeCloud IQ - Site Engine version 22.3 or later. Older versions (including Extreme Management Center) will not recognize devices running Switch Engine.