Not with the same Max version, but it can be done using separate Max installations. For example, lets say you want to install an old version of RailClone in Max 2018 and the Latest Version in Max 2019:
- Install the current version of RailClone in Max 2019, using the default installation options.
- Run the installer of the old version of RailClone. Select Advanced Installation from the Installation Type screen then click Next.
- Click through to the choose component screen and expand the Plugins tree. Select the versions of Max you wish to install.
- From the next screen, modify the destination folder, e.g. to C:\Program....\RailClonePro1\
- Click next to Install.