Q-Chem Upgrades

There are two types of Q-Chem releases each year: a major release (generally in May-June), and follow-up updates (generally 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 6.1 to 6.2), 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.

Navigate to the directory containing Q-Chem, for example:
```
cd /opt/qchem/6.2
```
Launch the update script:
```
./qcupdate.sh
```

If you encounter problems with the update script, please email our support team at support@q-chem.com for assistance.

Updates on Windows

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