File: autoconf.info, Node: Autoconf 1, Next: Autoconf 2.13, Prev: Obsolete Macros, Up: Obsolete Constructs 18.5 Upgrading From Version 1 ============================= Autoconf version 2 is mostly backward compatible with version 1. However, it introduces better ways to do some things, and doesn't support some of the ugly things in version 1. So, depending on how sophisticated your ‘configure.ac’ files are, you might have to do some manual work in order to upgrade to version 2. This chapter points out some problems to watch for when upgrading. Also, perhaps your ‘configure’ scripts could benefit from some of the new features in version 2; the changes are summarized in the file ‘NEWS’ in the Autoconf distribution. * Menu: * Changed File Names:: Files you might rename * Changed Makefiles:: New things to put in ‘Makefile.in’ * Changed Macros:: Macro calls you might replace * Changed Results:: Changes in how to check test results * Changed Macro Writing:: Better ways to write your own macros