"IBM had long given up on it, even allowing another company to maintain the software in 2001. (These days, a firm named Arca Noae sells an officially supported version of OS/2, ArcaOS, though most of its users are in similar situations to the MTA.)"

So I suppose there are still updates. As an aside, at $129 for the personal edition [0] I want to pick it up just for the novelty of having an OS/2 machine running on modern hardware.

[0] https://www.arcanoae.com/shop/arcaos-5-personal-edition/