1. I think this whole thing can be rewritten using API factory function. And usage will be like

const { getApi } = services.api;
const api = getApi(version='V4',tokenV3)

This might need change on the community app side but it will generic for next versions.

2. I think we should remove every mention of v4 from the docs, there are many places where there is v4. Probably in a month or two, we will be launching v5
   https://github.com/topcoder-platform/topcoder-react-lib/pull/33/files search for v4