The format of products is slightly different in 3.5 and 3.6 - therefore the normal way is to have a thread in each, with the appropriate XML file attached to each (zipped please). If the mod does not use products at all then you could just have a thread in the 3.6 forums, saying it also works on 3.5. We don't allow 'redirect' threads from 3.5 to 3.6.