As in the article, it doesn't apply to the steam version, only standalone (which can autoupdate as well).
Btw, I'd appreciate good resources on this
The weird thing is that the Steam version does allow you to register for the free upgrade key, but it won't take it (for me).
The cool thing is if you download the standalone, non-Steam version and get the free upgrade key, you can then buy the NEXT upgrade for $50 which does include a Steam key.
Or in other words, you can get Game Maker Studio Professional for $50 on Steam this way.
(be sure to read the entire conversation and not just the main/big tweet)