How can I download the GUI of version18?

How can I download the GUI of version18 again? I only find the version19 online, but connot find the version18. I want to know the website to download the GUI of version18. Thank you very much!

When installing with the conda command, specify the version:
conda install mfix=18 -c https://usr:key@mfix.netl.doe.gov/conda/dist