After upgrading to Ubuntu 14.04.01, I ran into two issues: One with Apache2 and one with Samba 4.
Apache has been upgraded from 2.2.22 to 2.4.7. The content was no longer accessible. The site configuration directives Order, Allow and Deny such as
Allow from all
are now replaced with the Require directive. Detailed information can be found at Apache Module mod_authz_core.
Samba has been upgraded from version 3.6.3 to 4.1.6. The “valid users” behavior changed. It works if the user given in the “force user” directive is listed in the “valid users”. For example, datacloud has to be listed in the “valid users”.
valid users = ctheroux,datacloud
force user = datacloud