When running 4D Client 2004, to connect to 4D Server both client and server need to be running the same release of 4D. In past versions 4D allowed different release clients and servers to connect. For example, a 4D Client running 2003.7 was able to connect to 4D Server running 2003.6. Although this was never officially supported by 4D, it was technically possible, and then could be troubleshot by the user. With the advent of 4D 2004 this is no longer possible. The 4D Client, for example a 2004.4 client connecting to a 2004.5 server, will receive an error message: "The version number of 4D Server is incompatible with the version number of 4D Client."
If you need to be able to upgrade your older clients automatically, there is an automatic update feature for 4D Client which is discussed in the following Tech Tip: