The standalone LWIP port has been replaced with the LPCOpen version of LWIP. The LPCOpen version supports more examples and more boards. The last official update for the 'lwip_lpc' is v1.10. The online GIT repo may have newer updates than the v1.10. release. IF YOU WANT TO USE LWIP, YOU SHOULD USE THE VERSION IN LPCOPEN.
This is the NXP LWIP port for the LPC devices and boards. See the project pages at http://www.lpcware.com/content/project/lightweight-ip-lwip-networking-stack for more information including version history and upcoming changes.