Notes on upgrading from an older release
========================================
+o Upgrading from a version prior to 1.6.9:
+
+ Starting with sudo 1.6.9, if an OS supports a modular authentication
+ method such as PAM, it will be used by default by configure.
+
+ Environment variable handling has changed significantly in sudo
+ 1.6.9. Prior to version 1.6.9, sudo would preserve the user's
+ environment, pruning out potentially dangerous variables.
+ Beginning with sudo 1.6.9, the envionment is reset to a default
+ set of values with only a small number of "safe" variables
+ preserved. To preserve specific environment variables, add
+ them to the "env_keep" list in sudoers. E.g.
+
+ Defaults env_keep += "EDITOR"
+
+ The old behavior can be restored by negating the "env_reset"
+ option in sudoers. E.g.
+
+ Defaults !env_reset
+
+ There have also been changes to how the "env_keep" and
+ "env_check" options behave.
+
+ Prior to sudo 1.6.9, the TERM and PATH environment variables
+ would always be preserved even if the env_keep option was
+ redefined. That is no longer the case. Consequently, if
+ env_keep is set with "=" and not simply appended to (i.e. using
+ "+="), PATH and TERM must be explicitly included in the list
+ of environment variables to keep. The LOGNAME, SHELL, USER,
+ and USERNAME environment variables are still always set.
+
+ Additionally, the env_check setting previously had no effect
+ when env_reset was set (which is now on by default). Starting
+ with sudo 1.6.9, environment variables listed in env_check are
+ also preserved in the env_reset case, provided that they do not
+ contain a '/' or '%' character. Note that it is not necessary
+ to also list a variable in env_keep--having it in env_check is
+ sufficent.
+
+ The default lists of variables to be preserved and/or checked
+ are displayed when sudo is run by root with the -V flag.
+
o Upgrading from a version prior to 1.6.8:
Prior to sudo 1.6.8, if /var/run did not exist, sudo would put