Some operating systems are moving towards making 64-bit the standard and maintaining 32-bit for compatibility purposes. To be compatible with this shift, new features can be implemented using a 64-bit architecture and in turn may only be used with a 64-bit version of the application.
There are already some commands that have been created that are only available in the 64-bit versions of 4D. To see if a command is 64-bit only, check the documentation for the command and see if the properties displays the "Not for 32-bit versions" icon:
The documentation also displays a list of commands that are 64-bit only when clicking on the icon:
If these commands are used in a 32-bit version of 4D, unexpected behavior can occur and 4D may not throw an error. For example the Cache info command created in 4Dv16, when used in one instance of a 32-bit 4D no error is triggered and the command appears to execute properly, but looking at the results some data is missing.