From 6 to 7:
export GEM_HOME=/opt/ruby_gems
export LC_ALL=C
gem1.8 uninstall mysql
gem1.8 install mysql —version=2.8.1
From 7 to 8:
export GEM_HOME=/opt/ruby_gems
export LC_ALL=C
gem1.8 uninstall passenger
gem1.8 install passenger
apt-get install apache2-dev
/opt/ruby_gems/bin/passenger-install-apache2-module
Plus adjustments in the corresponding module config files of Apache in /etc/apache2/mods-enabled.