Check you have the correct versions of Ruby and Rails, you need the following;

ruby 1.8.6, 1.8.7
Rails 2.3.11
Rack 1.1.1

so;

ruby -v
rails -v

I read that ‘rake about’ would tell you what version of rake is installed but I could not get it to work. ‘rake -T’ didn’t even show the rake about command so I assumed that the rails version is out of date so updated it to the needed version for redmine;

gem install -v=2.3.11 rails --include-dependencies

This installed rack version 1.1.2 but here’s hoping that won’t cause any problems.

Ready for the upgrade now, first backup mysql.

/usr/bin/mysqldump -u root -p redmine | gzip > /tmp/redmine_`date +%y_%m_%d`.gz

Copy the files somewhere

cp -R /opt/redmine /tmp/redmineBackup

Now perform the update;

svn update

I needed to add some more gems to make the database update work;

gem install -v=0.4.2 i18n

Update the database;

rake db:migrate RAILS_ENV=production

Update any plugins

rake db:migrate_plugins RAILS_ENV=production

Generate a session_store.rb

rake config/initializers/session_store.rb

Thats it.