The v3 version and any previous non-v3 versions are identified as different products in the host/daw software, which means that when the v3 version of a plug-in is installed it will co-exist in parallel with any previous installed version and will NOT replace the previous version of the plug-in.
As all previous non-v3 versions are 32-bit only they will only work in host versions supporting 32-bit plug-ins. If the host software is no longer supporting 32-bits, as with Pro Tools when it’s updated from PT10 to PT12 (PT10 supports 32-bits AAX and PT12 only 64-bit AAX) the previous non-v3 versions can’t be used in the host anymore. To maintain backward compatibility with older sessions, a 32-bit compatible version of the host should then be kept installed in parallel with the newer 64-bit compatible version.
Using the plug-in’s built in preset manager (not the host preset manager) all saved presets can be exported from the previous non v3 version to a preset file which can be imported into the v3 version of the plug-in.
Please note that all pre-v3 versions are no longer supported and we recommend, if possible, upgrading to the v3 version, and when doing so, if required, assuring backward compatibility with older sessions as stated above.