One only needs to take a look at the press images to see that they remain soldered on - https://www.apple.com/newsroom/images/product/mac/standard/A... for example, there's just no space for SODIMM's to fit.

Really annoying they continue to do this, especially given they charge excessive markup on memory upgrades (2x32GB DDR4 SODIMMS average $250-300, Apple charges you $800 for 64GB of memory).

That is speculation based off the wording they used in the description. He reached this conclusion because it said RAM/SSD were "not user accessible" and they used to say "built into the computer" - no one really knows the answer. I imagine they remain soldered.