32-bit support for ZBrush was discontinued with ZBrush 4R7.
In the years that have followed, we maintained support of that version for as long as possible for the benefit of existing customers who still had older systems. However, we are no longer able to do this as the activation system has been retired.
If you have a 32-bit computer and still have ZBrush 4R7 installed you will be able to continue using it. But if something happens that makes that impossible, you will not be able to use ZBrush until such time as you upgrade to a new computer.
Once you have a 64-bit computer, you will be able to upgrade your license for free to get the most current version to which you are entitled and will be able to immediately start taking advantage of not only the newer features but also the faster speeds and higher polygon counts that come with 64-bit software.
New purchases are automatically the most current version. The licensing is not backwards compatible to ZBrush 4R7 so it will not be possible for us to deliver that version to you. You would not be able to run it. If you do not have a 64-bit computer, please do not purchase ZBrush, ZBrushCore or download ZBrushCoreMini. None of them will function on 32-bit computers.