Either the server needs to update or you need to update.
If you have already purchased Minecraft PE, then update the game.
The next update for minecraft pe is expected soon with a lot of addition features.
Yes
next update hopefully
In Minecraft PE the horses will come soon since the pocket edition will soon get that update.
Fish server
You might have to update your minecraft
Minecraft: Pocket edition will update whenever you choose, as long as an update has been released to the public.
As of 01 May 2015, you are unable to get a horse in minecraft PE, it may be added in a future update.
As of yet, you cannot make a snow golem in Minecraft PE. This will come in a future update.
An "out-dated-client" means someone needs to update their Minecraft app to the latest update.