yum normally hides packages on the exclude list in yum.conf. As a result, yum update does not show which versions of excluded packages are available. Use yum shell instead to check whether those packages have updates. For example, /etc/yum.conf contains exclude=php*, hiding PHP updates. yum update cannot show which PHP version is available, but yum shell can.

yum shell

Loading “fastestmirror” plugin Setting up Yum Shell

config exclude ’ ’ list updates Setting up repositories Reading repository metadata in from local files Excluding Packages in global exclude list Finished Updated Packages … pfmon.x86_64                         3.2-0.060926.5.el5      base php.x86_64                               5.1.6-23.2.el5_3            updates php-cli.x86_64                        5.1.6-23.2.el5_3             updates php-common.x86_64           5.1.6-23.2.el5_3            updates php-gd.x86_64                        5.1.6-23.2.el5_3            updates php-imap.x86_64                   5.1.6-23.2.el5_3            updates php-ldap.x86_64                    5.1.6-23.2.el5_3            updates php-mbstring.x86_64          5.1.6-23.2.el5_3            updates php-mysql.x86_64                5.1.6-23.2.el5_3            updates php-odbc.x86_64                  5.1.6-23.2.el5_3            updates php-pdo.x86_64                     5.1.6-23.2.el5_3           updates php-pgsql.x86_64                  5.1.6-23.2.el5_3            updates php-xml.x86_64                     5.1.6-23.2.el5_3           updates … When you leave yum shell with quit or exit, the configuration returns to the settings in /etc/yum.conf.