4D Tech Tip 41408, Building
a built-client application for the right platform, mentions that the 4D Client portion of a merged, client/server application must be built on the target platform to which it will be deployed. I.e. the Mac OS merged 4D Client must be built on Mac OS, and the Windows merged 4D Client must be built on Windows.

There is one exception to this rule: the "upgrade client" used as part of the Automatic Client Update feature of 4D 2004 can be built on either platform. What is meant by "upgrade client" as opposed to "install client"? Here is some useful terminology:

Install Image
This term is used to describe all of the files that make up the installation of a merged application. For example a merged 4D Client install image contains the executable for the application, various libraries and resource files, etc. All of these files are collectively referred to as the “install image”.

Install Client
The install image of a merged 4D Client application. This is the software that would be manually installed on any given computer that will be used to connect to the merged 4D Server application.

Upgrade Client
The install image that is downloaded to the client machine for the purposes of automatically upgrading. This is not the software that would be manually installed on a given client computer. It is used by the automatic upgrade feature only.

The Install Client is the client that would be distributed, outside the scope of any 4D mechanism (e.g. on a CD, USB drive, a network share, etc.), to the users of the 4D database. Thereafter, assuming the Automatic Client Update features is in use, the Upgrade Client will automatically be installed on each client machine.

The Install Client must be built on the target platform. The Upgrade Client can be built on either platform. For more information about building merged client/server applications with 4D 2004, refer to the 4D 2004 Design Reference, which can be downloaded from the 4D Documentation page.