Apache 2.2.16 is currently the "best available version" of the HTTP Server. I made some changes to the source and need to recompile with OpenSSL. My question is, should I use OpenSSL 0.9.8o or OpenSSL 1.0.0a? The latter is a more recent, major release, but Apache couples HTTPD 2.2.16 with OpenSSL 0.9.8o in their binary offering. See "Win32 Binary including OpenSSL 0.9.8o (MSI Installer)" on the download page.
There is little to no documentation regarding Apache's decision here.