You can now store your color settings in themes and switch them easily.
You can also export & distribute your own themes.
Drastic performance improvements
In this change, we made efforts to identify a bunch of performance
bottlenecks and to resolve them. You don’t get frustrated anymore on
typing or opening files in particular with large files. Hanging on opening
large files is also resolved.
Toggling comment-out/uncomment
Selected text can now be comment-outed/uncommented via short-cut (⌘/) or
toolbar. The comment delimiters can be defined in each syntax style file.
More syntax highlighting colors
New “types,” “attributes” and “variables” keywords were added to syntax
highlighting colors.
New syntax style file format in YAML
The syntax style file format was changed from plist to YAML. It makes
style file ca. 60% smaller and helps to make your syntax via your own
script.
Yosemite support
CotEditor works well on OS X Yosemite. The new application icon is also in
Yosemite style.
More than 100 of improvements
There are more and more nicely improvements for you. Check out the
release notes for details.