Installed successfuly Firefox in my new iMac (Sierra 10.12.3) and the recommended Java 8 (they will not let me have 7). Unable to play live ... Disconnect between Apple's Sierra 10.12.3 and WIS (thru Firefox and Java) is too great ... Would have kept old computer if I knew beforehand, but donated it to lady friend that works for a nonprofit organization. Thanks for the inquiry. Best wishes to you ... (-:
Gus V.