For now yes, shosho is only set up to use ZS.
Need to enable users to BYO server in future releases.
Discussion
Do I have to make an account at ZS? 
Today was a bad day to make a new release but I was out of time!
Normally, no you do not need to make an account at ZS. Everything is taken care of within shosho.
Today, ZS is receiving a DDOS attack.
Shosho won't be particularly usable until that is resolved.
ok cheers. ZS was apparently having the same during last weeks RHR podcast, so you may want a default PlanB!
Okay good to know .