Starting in EXOS 16.2 and 21.1 the SSH module is integrated into the standard EXOS image. There is no longer a separate XMOD module needed for SSH.
Please refer following GTAC article as well:
https://gtacknowledge.extremenetworks.com/articles/Q_A/Where-is-the-SSH-module-for-EXOS/?q=SSH+module&l=en_US&c=Extreme_Software%3AExtremeXOS_EXOS&fs=Search&pn=1
Best Regards,