You can discover the client software version using:

# lctl get_param version
lustre: 2.3.61
kernel: patchless_client
build:  v2_3_61_0-g997d2b5-CHANGED-2.6.32

However, the version of the server software is not readily available to a user without access to the servers. The client knowns what version of the servers it is connected to.

It would be good to expose the server version on the client. A starting point for this information would be struct obd_connect_data:ocd_version