from my understanding, "warm vs hot" (both may be connected to net), however the difference is that the "warm" is a stand alone app of some sort & Not An Exchange! I don't claim to know everything, but this makes sense to me. You can research many articles on the topic, and a "warm" version is often listed as an option! 

watchmancbiz

If it's not cold, it's hot. The only way to be cold in any sense to be completely offline: no screens, no cables, no keyboard, no internet, no computer, no camera, period. 