To apply patches, you'll need to have downloaded and already built the source code distribution of XSPEC. Your HEADAS environment variables must also be initialized, such as with the headas-init script as you would if you were running XSPEC.

To update your XSPEC installation with ALL listed patches:

1. If you don't already have the patch installer tcl script (v4.16), download and place it in the heasoft-[ver]/Xspec/src directory in the source code distribution.
2. Download the latest patchfile into the same directory. There is no need to unzip/untar the patchfile since the installer will do that.
3. At the command line, launch the script by typing
   'tclsh patch_install_[ver].tcl', and that's all.

The script will detect which patches you've installed previously, copy the new code files to the necessary directories, determine whether complete or only partial rebuilds are necessary, and finally perform the rebuilds. Numbers listed in red indicate that the patch modifies the interface to one or more of XSPEC's libraries. These patches will generally cause longer rebuilds. If you have a local model library, it is recommended (though not always necessary) that you rebuild it with initpackage after applying red patches.