Hex Fiend Release Notes

Highlight selected bytes with a custom color via the "Highlight Selection" contextual menu
Fix Find controls clipped on macOS 10.13
Change banner views (Find, Jump to Offset, etc) to fixed heights to fix weird resizing
hexf can write to a non-existent file and diff two files via "hexf -d file1 file2"
hexf is now installed with escalated privileges
Make file permissions on save more secure (thanks wesdawg)
Added nullability annotations to the Framework for better Swift interoperability (thanks Ben10do)
Hex Fiend is now fully converted to Automatic Reference Counting

Add "Copy as ASCII" menu for always copying plain text as ASCII instead of the current encoding
Add preference to control default edit mode
Add search field to encodings window
When Find is activated its text field's text is now selected
Fix crash when copying more than 32KB of text
Fix hexf missing shebang (thanks Misty De Meo)

Add option to show data inspector ints as hexadecimal or decimal
Fix line number format not saving when clicking the column directly
Window now auto saves its position (thanks Daniele Cattaneo)
95% of code has been updated for Automatic Reference Counting
Removed File > Open Path. Use the standard open dialog's command-shift-G feature to open paths directly

Add hexf command line tool, which can be installed via the menu Hex Fiend > Install Command Line Tool. This is a simpler convience wrapper around the open command.
Fix showing the last line number with certain fonts (thanks Daniele Cattaneo)

Fixed a bug that caused exceptions when scrolling with a non-precise scrolling device (like a classic scroll wheel mouse).
Removed an .xcconfig file that was inadvertently being copied into Resources

Support for computing a binary diff between two files. This is a "true" LCS-based diff. Support for computing the diff lives in HexFiend.framework, while the document that presents it is in HexFiend.app.
Bookmark support. Bookmarks are little balloons that point at a range of bytes. They are not saved with the document.
Some support for attributes on ranges of bytes, which then can be translated into visual styles (such as colors).
Hex Fiend now has a privileged helper process ("Fortunate Son"), which can be used to read raw devices, root owned files, etc. Communication is via MIG.
Transient untitled document support. That is, if there is an untitled document that has never been edited, its window gets used by any document that's opened.
Undo can now be preserved across saves, when doing so doesn't require too much memory.
It looks more 3D. It's like you're really inside a hex editor!
Many more bug fixes representing a few years of work.