Improved performance with more complex drawings. 
New Features:
Support for Apple Pencil Double Tap Gestures.
When drawing with the Pencil, Asketch now switches to zoom first mode (pinch gesture controls zooming); Finger drawing reverts to focus circle mode. 
You can now hold down the Undo/Redo button for rapid unwind/rewind.

Fixed a crash bug with the gallery, and made some performance improvements. Resolved an issue where old drawings would not fill screen entirely.

Fixed bug where hint message on Force Sensitive devices would not clear correctly.

Improved touch gesture drawing functionality: Asketch tracks the surface area of the touch used to draw and will toggle between normal and soft shading modes depending on the context of the drawing (how sketchy it already is) and what the current focus level is.
Fixed "Cross Drawing" functionality: Shading will happen between strokes. This is a legacy setting and is disabled by default. Use the Settings app to enable this feature.
Rendering performance improvements.
Bug fixes.

Special thanks to Tanja Majerus for the use of her wonderful artwork.

Bug fixes and performance improvements. Added explicit "export layer" function via the long-press gesture. Improved touch area smudge control. Increased size of gallery thumbnails slightly on iPad. Added Fast Scroll arrows to gallery. Decoupled Apple Pencil and focus circle.

Performance improvements and bug fixes. Crisper line rendering at Retina resolutions. Maximum line width increased.

Fixed corruption issue with undo/redo

Squashed some bugs.

Improved line drawing performance slightly.
Fixed problem with hint text getting clipped.
Added accidental stroke undo when accessing the focus circle.
Fixed bug where 3D Touch incorrectly identified.

Pressure sensitive drawing on devices with 3D Touch support.
Simplified drawing mode available on 3D touch devices prioritizes zooming, and disables the focus circle.
New color picker tool. (Dragging the top color picker dot)
Copy operation now copies top layer at current zoom level.
New pointillism pencil rendering filter.
New context sensitive help hint system.
Countless bug fixes.

Fix for crash problems under iOS 9.
Fix for copy/paste image warping.
Fix for long press for copying not working on pressure sensitive devices

Fixes crash bug in color picker for users using iOS9
Fixes screen orientation corruption problem under iOS9
Changes to focus circle to give better feedback.

Background canvas is now 2X screen resolution. Less pixelation while working on zoomed images!

Fix for corrupted images when copying or exporting.

Bug fixes.

Bug fixes and stability improvements. Improved UI responsiveness.

Fixed iOS 8 Landscape mode problem.
Added 2 more shades of gray to the paper.
Added ability to share via iOS 8 Share sheets.
Better support for iPhone 6 and 6+ resolutions.

Fix for iOS 8 crash issue.

Color:

Tap a pencil (or press and hold) to display black, white and color options. Press the color dot to bring up the color palette. Tapping the active tool cycles between black, white, and the currently selected color.

Improved zoom rendering:

All pencil rendering is consistent regardless of zoom level. Previous versions of ASKetch rendered the pencils differently in different zoom levels.

Improved hard pencil:

The hard pencil now has a much wider range of rendering across the different focus levels. This allows for much tighter control, cleaner lines and smoother shading.
(A Settings option exists to revert to the 1.9.1 pencil)

Soft Pencil Blurring:

At the soft pencils least focused setting. Rendering is slightly blurred to soften the output. (This can be disabled via Settings)

Updated gallery view:

The Gallery now has explicit export and delete options. You can select multiple drawings at once and perform an action on all of them simultaneously.

Gray and Black colored paper options:

Vertically Swipe the blank/new drawing option in the gallery to switch between three different paper colors

Layer Exporting:

Press & Hold the drawing to bring up copy/paste/export options. All Options here act on the active layer and will not include the background.

Fixed a problem where pasting into other applications was not working correctly.

Re-enabled the three-finger tap for undo.

Solved a problem where blank drawings would sometimes appear in the gallery.

Added a setting to disable upward swiping for menu.

1.9 Changes:

New Smudge Tool: Turn the eraser to full transparency (all the way clock-wise) and it can be used as a smudge tool instead of an eraser.

Copy & Paste:
Use a long press action to bring up the copy/paste menu. (Note: long press to bring up the menu has been deprecated.)
Note that copying in ASKetch only grabs the topmost layer, and not the white background.

Access the Menu via a swipe from bottom of screen: In addition to the two-finger tap, the menu can now be activated via swiping upwards vertically from the bottom of the screen.

Setting to disable Landscape mode: Go into settings on the iPad, select ASKetch, and turn off "Allow Landscape" to only support Portrait modes.

Setting to control the long-press threshold: Go into settings on the iPad, select ASKetch, you can use the slider to increase the amount of time before the copy/paste menu presents.

Improved UI responsiveness on 3rd generation iPad.

Numerous bug fixes.

New Smudge Tool: Turn the eraser to full transparency (all the way clock-wise) and it can be used as a smudge tool instead of an eraser.

Copy & Paste:
Use a long press action to bring up the copy/paste menu. (Note: long press to bring up the menu has been deprecated.)
Note that copying in ASKetch only grabs the topmost layer, and not the white background.

Access the Menu via a swipe from bottom of screen: In addition to the two-finger tap, the menu can now be activated via swiping upwards vertically from the bottom of the screen.

Setting to disable Landscape mode: Go into settings on the iPad, select ASKetch, and turn off "Allow Landscape" to only support Portrait modes.

Setting to control the long-press threshold: Go into settings on the iPad, select ASKetch, you can use the slider to increase the amount of time before the copy/paste menu presents.

Improved UI responsiveness on 3rd generation iPad.

Numerous bug fixes.

Fixed issue that would cause random crashes.
Fixed problem with double-tap settings not being honored.
Double-tap is now off by default.

Added Twitter support in iOS 5 (Twitter must be configured in the Settings App first for it to appear as an export option)

Added Settings option to disable the Adaptive Eraser. This reverts to the 1.7 eraser functionality.

Minor modification to hard pencil to allow for lighter transparency value. This was changed due to user feedback.

Fixed memory leak with eraser.

--1.8 Modifications--

New Transform functionality: Zoom out of the image when menu is displayed to engage transform mode. This will give you the ability to permanently re-scale the image. Zooming in behaves as it did previously.

Improved pencil detail control: Focusing in will temporarily suspend drawing to other strokes. Focusing out resumes normal shading.

Improved eraser control: The eraser resets itself upon selection to a default state, which will eraser very lightly. If you continue to erase quickly over the same area, the eraser will draw progressively harder. This allows for less of a need to manually control the eraser transparency, though that option is still available through the twist gesture.

New email functionality: Pressing and holding gallery image allows for direct emailing as well as export to photos.

Orientation aware gallery: Landscape drawings have a landscape thumbnail.

Improved Stability on first generation iPads.

Autosave: Drawing is quick-saved every 30 seconds. As always, opening the gallery explicitly saves the drawing.

Minor UI improvements.

A special thanks to: Maurizio De Bellis (http://mauriziodebellis.blogspot.com) for the use of his wonderful art.

If you have questions or comments, please email me at: support@akernsoftware.com

New Transform functionality: Zoom out of the image when menu is displayed to engage transform mode. This will give you the ability to permanently re-scale the image. Zooming in behaves as it did previously.

Improved pencil detail control: Focusing in will temporarily suspend drawing to other strokes. Focusing out resumes normal shading.

Improved eraser control: The eraser resets itself upon selection to a default state, which will eraser very lightly. If you continue to erase quickly over the same area, the eraser will draw progressively harder. This allows for less of a need to manually control the eraser transparency, though that option is still available through the twist gesture.

New email functionality: Pressing and holding gallery image allows for direct emailing as well as export to photos.

Orientation aware gallery: Landscape drawings have a landscape thumbnail.

Improved Stability on first generation iPads.

Autosave: Drawing is quick-saved every 30 seconds. As always, opening the gallery explicitly saves the drawing.

Minor UI improvements.

A special thanks to: Maurizio De Bellis (http://mauriziodebellis.blogspot.com) for the use of his wonderful art.

If you have questions or comments, please email me at: support@akernsoftware.com

Bug fixes:
Fixed pencil swipe gesture problem.
Fixed eraser rendering glitch.
Added swipe gesture for pencil switches while drawing:
Use two finger downward swipe to toggle the active pencil.
Use two finger horizontal swipe to toggle between eraser and pencil.
Use three finger tap to undo last stroke.

Double-tap for the menu now disabled by default. You can still use the iPad settings to re-enable this.

Slightly improved quality of hard pencil "other stroke" shading.

Changed gallery functionality:
Dragging a picture off of the strip will now delete it permanently. (no longer clones)
Cloning now accomplished via a reverse pinch of the thumbnail to split the drawing into two.
To export simply touch and hold the drawing in the gallery.

A special thanks to: Maurizio De Bellis (http://mauriziodebellis.blogspot.com) and Yvonne Schmidt, MA from New Mexico for the use of their wonderful art.

If you have questions or comments, please email me at: support@akernsoftware.com

Further stability improvements.
Fixed problem with eraser where it was no longer drawing lines correctly when brush was made very small.
Improved speed of eraser rendering.

Fixed a crash bug with the gallery-strip.

Added previous pencil rendering as a legacy item. Use the Settings and select "Legacy Pencil" if you prefer how the application used to draw.

Remember: Swipe the buttons to flip between pencil types for different drawing effects. While drawing with the non-legacy pencil, use multi-touch to "focus" the blue circle for a harder/darker line. The legacy pencil still responds with a more pronounced spider-web look when unfocused, but draws more darkly.

Stability improvements & bug fixes.

Pencils auto-focus when drawing over the same stroke repeatedly without picking up your finger.

Menu auto displays at startup.

Remember: Swipe the buttons to toggle between pencil types for different drawing effects. While drawing (toolbar not visible), use multi-touch to "focus" the blue circle for a harder/darker line.

Stability improvements.

Performance improvements.
Gallery strip supports drag & drop; drop an existing picture onto the canvas to create a copy.
Soft pencil responds to the draw distance circle for lighter fill and better mid-tone control.

Gallery of saved works.
Redo (Swipe Undo button to get Redo)
Hard-pencil darkness is now adjusted with draw distance for greater control of mid-tones.

Numerous bug fixes.

Fixed older device compatibility issue.

Fixed iPod Touch menu failure bug.

iPhone support.
Pan and Zoom.
Two new pencils.
New pencil-input mode with better feedback; legacy mode available via settings.
Full transparency for the eraser.
Discrete eraser settings that are easier to select.
Fixed German language typo.

Double-tap reactivated. (Configurable via iPad settings)
Fixed memory leak with eraser.
Fixed saving to photo gallery so that active screen orientation is respected.
Localized for German.

Two finger tap now brings up menu. Double-tap and press-and-hold have been disabled.

Improved draw quality (darker lines and less skipping.)

Completely redesigned eraser.

Added two-fingered stroke for pencil shading effects.

Use pinch gesture to change size of eraser and pencil.

Localized for Spanish and French.