do you know the difference between software and firmware?
firmware, wikipedia
the touchscreen issues cannot be addressed by updating the operation system, but with firmware updates. But obviously not firmware updates solely, because there are differrences regarding the operation behavior of the touchscreens of firmware versions in combination with different touch panel models.
there is no official statement of Microsoft and I doubt that there ever will be any. . The notice, that the newest firmware for single SIM 535 devices (02060.00000.15053.2400x) enfolds its full impact solely on phones which have a built-in toch panel with the part number NOK/TOUCH PNL# CT2S1973-E TRULY´, is a consumer notice - not an official one.