Note

These are the 2.3.x to 3.0 upgrade instructions.

Upgrade instructions

(Debian) aptitude install libregexp-common-net-cidr-perl libregexp-ipv6-perl libhtml-quoted-perl libtext-password-pronounceable-perl libconvert-color-perl
(Other distributions) Install Regexp::Common::Net::CIDR, Regexp::IPv6, HTML::Quoted, Text::Password::Pronounceable and Convert::Color

rm -f rt/bin/rt-crontool rt/bin/rt-mailgate rt/bin/standalone_httpd rt/config.log rt/config.status rt/etc/upgrade/3.8-branded-queues-extension rt/etc/upgrade/3.8-ical-extension rt/etc/upgrade/generate-rtaddressregexp rt/etc/upgrade/split-out-cf-categories rt/etc/upgrade/vulnerable-passwords rt/sbin/rt-attributes-viewer rt/sbin/rt-clean-sessions rt/sbin/rt-dump-database rt/sbin/rt-email-dashboards rt/sbin/rt-email-digest rt/sbin/rt-email-group-admin rt/sbin/rt-server rt/sbin/rt-shredder rt/sbin/rt-validator rt/t/data/configs/apache2.2+fastcgi.conf rt/t/data/configs/apache2.2+mod_perl.conf rt/lib/RT.pm rt/Makefile

make clean; make configure-rt; make install-perl-modules
make intall-perl-modules
As the freeside UNIX user, run freeside-upgrade username, passing the username of an internal Freeside user.
If freeside-upgrade hangs, try stopping Apache, all Freeside processes, and anything else connected to your database, especially on older PostgreSQL versions.
make install-docs

Edit /opt/rt3/etc/RT_SiteConfig.pm and remove the line reading Set($WebDefaultStylesheet, 'freeside2.1');
As the freeside UNIX user, run /opt/rt3/sbin/rt-setup-database --dba freeside --prompt-for-dba-password --action upgrade