"In a separate thread, we should discuss workarounds/fallback plans so that we are prepared either way."
NTLM support of one form or another is critical for most of the Windows-based repositories. This includes SharePoint, Meridio, and LiveLink. For HttpClient 4.x, they went so far as to remove even 3.x's limited support for NTLM. What they did instead was to point you at jCIFS and tell you how to write an authentication provider using some of the jCIFS methods to do the proper signatures. So, our options are (appears to me): (1) Get the NTLM implementation accepted, and preferably integrated upstream into HttpClient 4.x. (2) Convert everything to HttpClient 4.0, and either provide some kind of reflection-based hook for it that will make use of jCIFS if it is present, but fall back to no NTLM support if not, or better yet, add an authentication provider registry to HttpClient 4.0 that would make everyone's life easier in the long run. Note that there's a real problem with testing here - I don't have access to (say) a SharePoint server on an NTLMv2-protected domain right now, so how are we to check whether this works? Karl