That’s a certification process conclusion and the announcement of a date.
Do you really believe they certified their next phone, and then confirmed September, but for a totally different product (not certified, so, impossible to sell in September)?
If I dare, that would be more speculative than me 
.
The only uncertainty here is why they are announcing this has the potential of ‘changing the world’. I personally doubt just switching 5G would be enough for this. Some speculate, indeed, that there may be an OS evolution, or a new deal with Google. But, to me, that’s the only speculation left.
And to get back to this thread, I stand by my position : the OP should wait a couple weeks, if she can, because there will be a (small) surge in second-hand Fairphones once the new model is out.