1. Don’t execute anything from the installation steps before or after your update
  2. Make sure that you have a working database backup before you start the update
  3. Read the UPGRADING guide and the release information to check if there are further manual steps required for one of the version between yours and the new one

Update process

Change into your Kimai directory, then fetch the latest code and install all dependencies. You might have to prefix the composer and bin/console commands with sudo -u www-data (depends on your setup):

git fetch --tags
git checkout 1.3
composer install --no-dev --optimize-autoloader

Refresh your cache:

bin/console cache:clear --env=prod
bin/console cache:warmup --env=prod

And upgrade your database:

bin/console doctrine:migrations:migrate

Important: Finally execute the version specific tasks from the UPGRADING guide.