Upgrading from Version 4 and Earlier
By default, Version 5 is installed in a separate directory and not over earlier versions. The files used to save default settings are also separate and will not overwrite any previous preferences files. You must use a new password for Version 5.
Packages written with earlier versions
The performance of application packages written for earlier versions of Mathematica may be affected by changes made to some functions in Version 5. However, most Mathematica applications from Wolfram Research will run normally. Visit www.wolfram.com/products for more information about individual application packages or see Appendix A.13 in The Mathematica Book for a list of incompatibilities.
Version 5 supports remote kernel connections to kernels from Version 3.0.1 or later. You may also connect a front end from Version 3.0.1 or later to a Mathematica 5 kernel.
Version 5 can use the TCP/IP device to make kernel connections. Earlier versions of Mathematica do not support TCP/IP connections. If you are using Version 5 to connect to an earlier remote kernel, you must use MathLink devices available for earlier versions. See support.wolfram.com/mathematica/kernel/configure/general/ for more information.
Using the Applications Library with Version 5
The performance of application packages written for earlier versions of Mathematica may be affected by changes made to some functions in Version 5. However, most Mathematica applications from the Applications Library will run normally. Visit www.wolfram.com/products for more information about individual application packages or see Appendix A.13 in The Mathematica Book for a list of incompatibilities.
Application packages need to be copied into a specific directory, based on whether you have administrative privileges:
You can use the same command from an earlier version to load the package. If Version 2 notebooks are included in the package, you can convert them simply by opening them in Version 5.
Notebooks in Version 5
Notebooks created before Version 3 in 1996 carry the .ma file extension and have a different structure than notebooks created in Version 3 and later. A notebook is now a Mathematica expression stored in a platform-independent file with the extension .nb. All the information necessary to open the notebook is stored in the .nb file.
When you open a notebook that was created with Version 2.2 or earlier in Version 5, a dialog box will appear that allows you to convert your notebook automatically. You have the option of converting input and output cells into StandardForm cells, which will automatically typeset characters and formulas.
You can also use the kernel function NotebookConvert to convert notebooks to the newer format. NotebookConvert is useful for converting a large number of notebooks without opening them individually in the front end.
NotebookConvert[notebook] converts notebooks to the new format and saves the result in a file. The name of the new notebook is based on the name of the old notebook, except that the extension .nb is used in place of the .m or .ma extension that was used in previous versions of Mathematica.
Although NotebookConvert is a kernel function, the actual conversion is handled by the front end, so notebook names must be specified in a way that is appropriate for the front end, rather than for the kernel. If the notebooks that you want to convert are not in the same directory as the directory from which you launched the front end, then the notebooks should be specified by giving the directory path relative to the front end directory, or by giving an absolute pathname.
You can use Scan[NotebookConvert, list] to convert all of the notebooks listed in list. If the kernel and the front end are running on the same computer, you can use NotebookConvert[dir] to convert all of the files in the directory dir.
T I P S
You can specify the name of the new notebook explicitly using NotebookConvert[old, new], which saves the result in a notebook with the name new.
NotebookConvert also supports the Interactive option, which allows you to specify whether you want to see the Save dialog box if a notebook with the same name as the new notebook already exists.