GO-21 SciRPN26.5.1

GO-21 SciRPN simulates the venerable HP-21 Pocket Scientific Calculator from 1975. Virtually indistinguishable from the real item in operation, GO-21 is a powerful yet simple retro calculator.

. RPN (Reverse Polish Notation)
. 10-digit LED calculator display, 10-99 to 10+99
. Four stack registers with roll down
. One storage register with arithmetic memory operators
. Math, trigonometric, polar/rectangular, logarithmic, power and other miscellaneous functions
. One additional window with views of:
◦ stack/storage registers
◦ keystroke log
. Copy-from and Paste-to the calculator display
. Simple Paper Tape annotations

Version History - Repair broken icon and update documentation.
- Update to Apple OS versions 26.5.1. 26.5.1 Jun 11 - ENG display format & other bug fixes and enhancements.
- Provide a complete PDF hardcopy of the HTML user manual, including an index.
- Minimum macOS version now 13.0 (Ventura).
- Minimum iOS / iPadOS / tvOS versions now 16.0.
- Update to Apple OS versions 26.5. 26.5 May 31 - Update for iOS 18.0, iPadOS 18.0, tvOS 18.0, macOS 15.0. 7.1 09/17/2024 - New Settings option, Auxiliary View Assist, enables draggable buttons for quickly opening / closing the stack window.
- New Settings collection, Accessibility, groups High Visibility Display, Magnify Calculator and Auxiliary View Assist.
- The Settings option Auto-On now defaults to YES.
- Battery power level reporting has changed in iOS, iPadOS and macOS: adjust power level monitoring algorithm to compensate.
- Bug fixes, miscellaneous improvements and internal modernization.
- Refresh documentation.
- Update for iOS 17.5, iPadOS 17.5. tvOS 17.5, macOS 14.5. 7.0 05/15/2024 - Miscellaneous improvements recommended for everyone.
- Update for iOS 17.4, iPadOS 17.4. 6.6.3 03/09/2024 - Improved look when magnified. 6.6.1 02/22/2024 - New Settings option "Magnify Calculator", which creates a zoom-in effect that clips the periphery of the device body.
- Modern color picker for devices running iOS 14 or newer.
- Miscellaneous bug fixes.
- Update for iOS 17.3.1, iPadOS 17.3.1, tvOS 17.3, macOS 14.3.1. 6.6 02/18/2024 - Support iPhone 14; cosmetic improvements for iPhones 5, 6, 7 and 8.
- Update for iOS 16, macOS 12.6, tvOS 16. 6.5 09/14/2022 - New external keyboard action: typing M invokes the multiply function, eliminating a shift.
- Nerd alert: iOS versions > = 14 and macOS versions > = 11 now use the modern PHPicker photo chooser rather than the venerable UIImagePicker.
- Minor bug fixes and improvements.
- Update for iOS 15.3.1, macOS 12.2.1, tvOS 15.3. 6.4 02/19/2022 - A blinking decimal point indicates battery power less than 5% (except Apple TV).
- New macOS Universal binary that runs on either Apple Silicon or Intel Macs.
- Update for iOS 14.3, macOS 11.1, tvOS 14.2. 6.3 12/20/2020 - Support iPhone 12, update for iOS 14.0.1. 6.2.1 10/14/2020 - Paper Tape Annotations now work on tvOS.
- Info enhanced when using tvOS.
- Experimental decimal math for the +, -, M+ and M- keys.
- Update for iOS 14.0, macOS 10.15.7, tvOS 14.0. 6.2 10/04/2020 - Update GO-21 SciRPN's tvOS documentation and focus navigation for consistency with GO-25 SciRPN and GO-29 SciRPN.
- Update for iOS 13.7, macOS 10.15.6, tvOS 13.4.8. 6.1.1 09/13/2020 - GO-21 SciRPN for Apple TV is now part of the universal purchase bundle.
- New background theme OS Appearance that tracks the OS's Appearance setting.
- 0^0 produces Error rather than evaluating to 1. 6.1 09/01/2020 - Unified App that runs on all your devices. 6.0 08/18/2020 - International hardware keyboard support for iOS and macOS.
- Similar to some CuVee Software products and with permission, add ability to annotate, clear, copy, email and print the Paper Tape. 5.7 06/27/2020 - Implement hardware keyboard support for Mac and iPad.
- Ensure conformance with Apple's 2020.06.30 App Store guidelines.
- Update for iOS 13.5 and macOS 10.15.5. 5.6 05/31/2020 - When selecting colors on macOS use the native color picker rather than the builtin iOS color picker. 5.5 03/20/2020 - Remember visibility state of the stack view and restore appropriately across restarts.
- Automatic Display Switching: ensure switch to SCI 7, and repair display formats FIX 8 and FIX 9.
- Tweak Display Engine LED segments A and F.
- Improved memory management. 5.4 01/31/2020 - For iPhones with a 5.5 inch display or larger there is a new Background Color or Picture setting. 5.3 01/15/2020 - Add a Setting, High Visibility Display, so it's easier to view the calculator display in a very bright environment. The X register is shown in black on a white background, and each tiny LED display segment is drawn 33% larger. 5.2 01/10/2020 - Mac Catalyst enhancements.
- Documentation updates. 5.1 12/27/2019 - Share common code with GO-25 SciRPN and GO-29 SciRPN. This great internal refactoring resulted in external changes including, but not limited to:
. Default display rounding method changed to Half Away From Zero, which may affect displayed results. Use Half To Even in Settings to revert to the previous behavior.
. New stack / memory Register and paper tape Keystroke views. Use the switch-views control to alternate between them.
. Use new Appearance dark / light module (WkWebView) to render HTML throughout.
- New Key Tap Feedback option Haptic Feel that uses touch feedback rather than sound to indicate a key tap, assuming your device includes the feature and that it is enabled in Settings.
- Update for iOS 13.3.
- Update for iPadOS 13.3 and macOS Catalina 10.15.2: this means that GO-21 now runs on your friendly Macintosh computer!
- Minimum iOS version is 9.0; minimum macOS version is 10.15. 5.0 12/22/2019 - Update for iOS 12.3.1. 4.15 07/15/2019 - Update for iOS 12.1.4.
- Documentation now supports BigCatOs Appearances. 4.14 03/24/2019