Are you sure it's free?
Yep, it's completely free... to include making the source code available as "public domain" There is no licensing of any kind, and no restrictions on its use (to include making money from it!)
I get a message that says that I should install something
The WRPN program requires the ".Net Framework" to be installed on the PC. Generally, you should install the latest version.
Download and install the latest .Net Framework from: http://www.microsoft.com/net/
Where can I get the User's Manual for the real calculator?
A PDF version of the original Owner's Guide can be found at https://literature.hpcalc.org/items/589
WRPN Privacy Policy
This application does not have any advertisements and does not collect any data at all! The application uses the following Android permissions:
- INTERNET - to get to the on-line users documentation
- WRITE_EXTERNAL_STORAGE - to save the calculator state between uses