Chapter 16. General Updates

The default value of first_valid_uid in Dovecot has changed in Red Hat Enterprise Linux 7

Since Red Hat Enterprise Linux 7.3, the default value of the first_valid_uid configuration option of Dovecot has changed from 500 in Red Hat Enterprise Linux 6 to 1000 in Red Hat Enterprise Linux 7. Consequently, if a Red Hat Enterprise Linux 6 installation does not have first_valid_uid explicitly defined, the Dovecot configuration will not allow users with UID less than 1000 to log in after the update to Red Hat Enterprise Linux 7.
To avoid breaking the configuration, redefine first_valid_uid to 500 after the upgrade in the /etc/dovecot/conf.d/10-mail.conf file. Note that only installations where first_valid_uid is not explicitly defined are affected by this problem. (BZ#1388967)

Incorrect information about the expected default settings of services in Red Hat Enterprise Linux 7

The module of Preupgrade Assistant that handles initscripts provides incorrect information about the expected default settings of the services in Red Hat Enterprise Linux 7 according to the /usr/lib/systemd/system-preset/90-default.preset file in Red Hat Enterprise Linux 7 and according to the current settings of the Red Hat Enterprise Linux 6 system. In addition, the module does not check the default settings of the system but only the settings for the runlevel used during the processing of the check script, which might not be the default runlevel of the system. As a consequence, initscripts are not handled in the anticipated way and the new system needs more manual action than expected. However, the user is informed about the settings that will be chosen for relevant services, despite the presumable default settings. (BZ#1366671)

Manually created configuration might not work correctly with the named-chroot service after upgrading

When you use the the named-chroot service and when you have your own manually created configuration files in the /var/named/chroot/ directory, the service might not work properly on the target system after the upgrade to Red Hat Enterprise Linux 7. The options section in the used configuration files must contain the session-keyfile and pid-file directives, such as in the following example:
session-keyfile "/run/named/session.key";
pid-file "/run/named/named.pid";
The Preupgrade Assistant modules do not check or fix the manually created files in the /var/named/chroot/ directory. To work around this problem, manually insert the lines above to the options section. If you do not have your own manually created configuration files in /var/named/chroot/, the configuration files of bind, including the /etc/named.conf file, are used. These configuration files are checked and fixed by the Preupgrade Assistant modules. (BZ#1473233)