I don't think there is going to be a new iPhone6SE next months. There will be a new iPhone 7. The iPhone SE is the 4" version of an iPhone which was released about 6 months ago. I don't see them releasing another SE that soon.
I think they were referring to the rumour that the next iPhone would be branded 'iPhone 6SE' because it will be an iPhone '6S S' so to speak, not a new design 'iPhone 7'.