Here we go again making assumptions without understanding what is really going on.
--> Populating transaction set with selected packages. Please wait.
---> Package smeserver-support.noarch 0:2.0.0-3.el4.sme set to be updated
--> Running transaction check
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-imap
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-gd
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-mbstring
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-cli
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-mysql
--> Processing Dependency: php-domxml for package: e-smith-horde
--> Processing Dependency: smeserver-locale-ru for package: smeserver-support
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-bcmath
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-ldap
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php
--> Processing Dependency: smeserver-locale-zh_CN for package: smeserver-support
--> Processing Dependency: php-common = 5.1.6-3.el4s1.10 for package: php-pdo
--> Processing Dependency: php-api = 20041225 for package: php-mcrypt
There are a lot of php stuff but the key line in there is that php-domxml is required by e-smith-horde. Nothing in there are all about smeserver-support. It is e-smith-horde requiring php-domxml that is starting this whole thing.
---> Package php-domxml.i386 0:4.3.9-3.22.15 set to be updated
And because it doesn't have a php-domxml for the php you have installed it tries to pull the best match it has which is a version for 4 not 5. It is all downhill from here.
--> Processing Dependency: php = 4.3.9-3.22.15 for package: php-domxml
Here we try and pull in php-4 because the php-domxml requires that version.
Error: Missing Dependency: php = 4.3.9-3.22.15 is needed by package php-domxml
And here is one (the real one) that is causing the upgrade to fail. It won't install php-4 because you already have php-5 installed.
If you really want to be able to upgrade try installing php-xml from the centosplus repo which provides php-domxml and everything should proceed fine after that.
Normando, don't take offense to this it isn't directed at you directly. There is a lot of bad advice given in the forums by individuals that don't fully understand what is going on. Taking stabs in the dark and trying stuff (that might appear to work) doesn't explain what the real issue is and doesn't solve the issue. The only place this really takes place is in the bugtracker.
The reason we wan't bugs raised is so the developers see what is going on and we can solve the issues correctly for everyone. We don't have time to trawl the forums for issues and there is no accountability or tracking of issues here. Please follow directions and raise bugs in the correct place so that we can fix the real issues the correct way.