Interactive RetroFlow is an open-source program licensed under the GNU General Public License, version 2, and is thus available for no-charge and can be redistributed per the terms of that license.
Interactive RetroFlow is written entirely in Python 2.7 and thus should run on any machine which has Python 2.7 installed. If you don't already have Python 2.7 you can get it here: https://www.python.org/. There are no plans to rewrite Interactive RetroFlow in other languages, eg Ruby, Java, Modula-3, Fortran, Cobol, Jovial or Python 3.
Interactive RetroFlow can export charts in SVG, PDF and Text formats. When exporting in PDF format, it uses the Python package "reportlab". If that package isn't installed then you will get a message saying so at startup. All other facilities of Interactive RetroFlow will work in the absence of reportlab, but you won't be able to export charts in PDF format.
To install reportlab, in most cases
pip install reportlab
will do the job. Full details consult: http://www.reportlab.com/opensource/
There is no fancy installer for Interactive RetroFlow: just download the appropriate version below then unpack it into a directory and follow the instructions in the "readme.txt" file.
The ".tgz" files contain Linux style LF line endings, while the ".zip" files contain Windows style CRLF line endings. Other than that they are identical.
Interactive RetroFlow was developed using the Rapyd-Tk rapid application development environment. In the unlikely event that you or anyone else is interested in doing some development work on RetroFlow, we hereby supply the Rapyd Project file which will allow you to work on the RetroFlow project using Rapyd-Tk.