Sorry but chances are, Apple will release an 11S (not new form factor) in 2020; just look towards the past 3 form factor changes for the probable answer:
4/4S/5/5S then 6/6S/7/8 then X/XS/11/(11S)? AND THEN the 12....
This.
People keep referencing the 8 plus/ X of 2017 as to why next year will be a complete redesign. I think this reasoning is ill founded. 2017 was an exception for a variety of reasons IMO. They were facing pressure from the several previous years of no design changes to a phone containing huge bezels in a world of shrinking bezels. Leaks at that time indicated that Apple released the X one year ahead of when it planned, which is probably why we did not get a plus model of the X. It was also the decade anniversary and I don’t think Apple could resist the “X” referencing it. But they couldn’t release the “7s” alongside it, so they had to call it the “8”.
Anyone expecting a X, XS, 11, 12, 12s is mistaken I think. I also don’t think Apple will go to a numberless system, as it becomes to difficult to differentiate the lineup. Will they’re be changes next year, sure, I just think there is way too much expectation as to what that change will be....Take rumors with a big grain of salt