iHP is not an original idea, nor development. There are a lot of emulators for the extraordinary HP 48 series calculators for almost any operating system which includes Linux, Windows, macOS, Android and iOS. Just to list some of them.
One of the most reliable emulators out there is EMU48 for Pocket PC 1.16+, which based on Emu48 1.56+ for Windows, and then was the source to m48, m48+ and then all of them sources iHP.
So first, my acknowledge to all the developers involved on the current iHP, and my thanks as a user of the fantastic calculator of my phone.
License:
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Source:
Source available upon request.