Make sure to switch a button above download link to 64-bit before pressing 'Download' button. If you wish to switch to 64-bit version, you should download it from the website front page. When you use an autoupdate in your current version, you will get a 32-bit upgrade to 3.2.0 by default. New 32-bit and 64-bit are not guaranteed to run and activate smoothly, so having an old version backup is worth for the first days of release. z3d files saved in current version of ZModeler if you wish to revert to older version for some reason. It is recommended to keep backup of your. z3d files created in any of these and further versions in any old version of ZModeler. Versions are cross-compatible in features and saved files, however you will be unable to open.
ZModeler 3 core have been upgraded to support 64-bit builds, starting from version 3.2.0 two versions will be available (32-bit and 64-bit) for download.