|Engine Initialization and Shutdown||Table of Content||FIX Message|
|Selecting FIX Version|
As the FIX protocol evolves, new versions will be released to you to extend the current functionality. OnixS .NET FIX Engine currently supports the following FIX versions: FIX 4.0, 4.1, 4.2, 4.3, 4.4, 5.0, 5.0 SP1, and 5.0 SP2.
ProtocolVersion enum is used to identify a particular version of the FIX protocol in the OnixS .NET FIX Engine.
To simplify development, as well as to increase code readability, OnixS .NET FIX Engine exposes separate namespaces for each version of the FIX protocol. Each of such namespace contains objects and definitions that are unique for the particular version.