The source has to the Compiled DLL has now been moved to the https://github.com/OpenTrading/mql4zmq/ to better document the changes we made in it from the original source.
As a convenience, we have checked in the binaries from that project to the src/mql4zmq directory. In theory the files in this project will always mirror that project, but that project is always master.
In addition to being a convenience, checking them in here makes it absolutely certain which DLLs we are testing against. The mql4zmq.dll here is from mql4zmq-2.2.0-v100.dll there. The libzmq.dll here is from libzmq-v100-mt-2_2_0.dll there.
Note that in the process, we have rolled back to ZeroMQ v2.2.0.
See the Installation page in the directory for instructions on where the DLL files in src/mql4zmq/pre-compiled/ go.