On Sep 4, 2018, at 6:22 PM, evan@evan-borden.com wrote:

* Breaking change: PortNumber originally contained Word32 in network byte order and used "deriving Ord". This results in strange behavior on the Ord instance. Now PortNumber holds Word32 in host byte order. [#347](https://github.com/haskell/network/pull/347) * Breaking change: stopping the export of the PortNum constructor in PortNumber.

Small correction, the port number of course was and remains Word16 not Word32. One might also note that to the extent that applications did use the PortNumber in SockAddrInet, and SockAddrInet6 structures, they likely relied on the Num, Enum and Integral instances, rather than using "PortNum" directly. Those instances made it possible to use numeric literals or "fromIntegral" to create "PortNumber" from port numbers. And this has not changed. The only thing that's no longer possible is direct use of the "PortNum" constructor with values already in network byte order. This should be a rare impediment, and the removal of the constructor means that all problems are detected at compile-time. So this is unlikely to be an issue for the majority of applications, which likely just use getaddrinfo() in any case, and don't build SockAddrInet* structures "by hand". -- Viktor.