2.6 beta (25 May 2016)
 
 * gradle support
 * improved MK54 skin
 * export/import to/from external files

2.4 beta (26 Nov 2013)

 * enlarged launcher icon
 * long touch on indicator hides/shows calculator switches
 * long touch on "Вкл" label acts as Menu button (for weird devices without this button)
 * redesigned preferences screen
 * synchronized state saving
 * major code cleanup
 * preferences for the new functionality added:
 ** grayscale screen mode (for e-ink screens)
 ** show/hide status bar
 ** buttons produce sound chosen by user
 ** buttons can react on touch and not on release

v2.3	(7 Oct 2013)

 * fixed state saving instability on leaving app
 * fixed layout resizing glitch
 * switching calculator off and state saving/loading became faster

 Added user preferences for:
 * type of on/off and angle mode switches (checkbox/radio buttons or slider)
 * vibration intensity
 * buttons outline
 * labels text size

v2.2	(24 Sep 2013)

 * fixed UI scaling issue on normal-mdpi screens
 * improved large-mdpi screens

 * added thin border around buttons

v2.1	(22 Sep 2013)

 * "MK 61 ↔ MK-54" button is now menu option (available when calculator is off)
 * "About" moved from settings to menu, now with usage hints

 * fixed calculator's display font size issue:
 * entering exponent should not split display into two lines (was an issue on some devices)
 * width should be fully used

 * ШГ→/ШГ←/↔ got better labels

 * fixed/improved layout on devices with low and medium resolution

v2.0	(16 Sep 2013)

 * added MK-54 emulation
 * application name was changed to "MK 61/54" to reflect the fact it supports both devices
 * when calculator is switched off, selector button chooses between "MK 61" and "MK-54"
 * save states remember which calculator type they were saved with
 * old save states use MK 61 device

 * added soft "Menu" button on devices that lack hardware menu button
 * added support for older Android versions, including Android 1.6
 * additional UI polishing for tablets

v1.7	(12 Sep 2013)

 * fixed ГРД angle mode switch position (was acting as Degrees mode instead of Grads)
 * saved states now can have names. Hint: load and save state to rename it.
 * use up to 99 saved states now instead of 50
 * added Russian user interface translation
 * a number of polishing UI tweaks on the main and settings screens


v1.6	(03 Sep 2013)

 * added "Settings" page to let user choose vibration and/or disabled screen auto-off
 * indicator font size fix for tablets

v1.5	(02 Sep 2013)

 * main screen user interface completely redesigned from the scratch
 * authentic look (as much as possible)
 * adaptive behavior that fits any screen from 2 to 10 inch
 * launcher icon redesigned
 * added slight vibration on button press, more sensible on angle mode change, even more intensive for on/off switch
 * screen never goes off even when nothing is touched for a long time

v1.4	(28 Aug 2013)

 * fix emulation for entering negative exponent
 * 10x speed increase - now works even on old Android devices
 * touch indicator to toggle fast/slow mode
 * on fast phone use slow mode for blinking
 * fixed key press detection
 * fixed indicator symbols size
 * stable states saving implementation - will be compatible with future versions

v1.3	(25 Aug 2013)

 * added "About" dialog
 * enlarged digits
 * added state saving/loading (up to 50 slots)

v1.2	(23 Aug 2013)

 * keep state after pressing Home or Back

v1.1	(21 Aug 2013)

 * first release to Google Play
 * fixed UI bugs
 * speed optimization

v1.0	(20 Aug 2013)

 * release candidate


Initial development	(Summer 2013)

 * porting Felix Lazarev's emu145 engine to Java
 * developing Android application from scratch
