Hi Folks, Larch 0.9.42 is now available, with installers for Windows, MacOS, and Linux at https://millenia.cars.aps.anl.gov/xraylarch/installation.html Version 0.9.42 fixes many problems, especially to the XAS Viewer GUI app which is now pretty close to a replacement for Athena but with better peak-fitting and with none of the limitations that were imposed by the outdated ifeffit library. For MacOSX, Version 0.9.42 can be installed with a standard Mac "pkg" installer file. If you have already installed Larch, you should be able to update to the latest version with conda update -c gsecars xraylarch on Windows, you may have to specify the full path with something like: C:\Users\<YourName>\AppData\Local\Continuum\xraylarch\Scripts\conda.exe -c gsecars xraylarch If you have any trouble upgrading, you can also simply remove the XrayLarch installation and reinstall using one the installers above. For Python programmers, Version 0.9.42 ends support for Python 2. No testing or packaging was done with Python 2 for this release, and going forward the master development branch will not work with Python 2. Please let us know if you having any questions, trouble, or suggestions. --Matt Newville