Which HTTP versions are supported?

Platform releases prior to 4.3.x.x support versions 0.9, 1.0, 1.1 and 2.0 of the HTTP protocol. The releases that use Gateway 4.3.x.x had their support limited to HTTP 1.1 and 2.0. The Gateway hotfix 4.3.5.1 expanded support to HTTP 0.9 and 1.0 as well.