WI400 require minimum I5OS release:
– V5R3 with latest  PTF
– program product 1ZCORE5 (ZendCore)
(references here: ZendCore)

or
– V5R4 with latest PTF
– program product 2ZSVRPI (ZendServer)
(references  here:  ZendServer)

Wi400 is certfied for new releases
– V6R1
– V7R1