The next v7.3 will be the last one with support for 32 bit. The actual reason is that the latest Open Cascade version 7.9.0 does not have 32-bit support. More precisely, they do not have 32-bit third-party components. The good thing is that We will be able to build smaller installers with less effort.

DGK 7.3 will be released sooner than planned. It will be a quick "service release" with only few, mostly performance-related issues fixed and no new features. It should be out in about a month.
The OCCT, renderer and other component updates and new features will go into v7.4, which most likely be out in December or January.