Q-Chem Upgrades

Q-Chem publishes three software releases each year: a major release in May-June, and two follow-up updates in August and December. The minor follow-up updates are free for all customers who have already purchased the current version, whether or not they have an active QMP subscription. If you are planning a major upgrade (for example, from Q-Chem 5.1 to 5.2, from Q-Chem 5.2 to 5.3, and so on), please follow the normal installation procedure or contact our user support team for instructions.

Updates on Linux and macOS

Following these steps will update your Q-Chem in-place. If you'd like to retain both, new and old, versions of Q-Chem, install into a separate directory instead.

Important: please ensure that you are logged in as a user that has write permissions in the Q-Chem directory.

  1. Navigate to the directory containing Q-Chem, for example:

    cd /opt/qchem/5.1
  2. Launch the update script


Updates on Windows

Q-Chem for Windows does not support in-place updates, and a separate copy must be installed instead.