Lotus software still exists as a subsidiary of HCLTech, an Indian IT company. They acquired it from IBM. While it was still owned by IBM, 1-2-3 was officially discontinued in 2014.

Legally, HCLTech probably still owns the rights to it, but since it hasn't been for sale for years, I would consider it abandonware and would not have many qualms about pirating it, especially as this is a port of "Release 3", from 1989.