# Important changes on CotEditor 2.0

CotEditor 2.0 includes some specification changes for customization from the previous versions. If you’ve used the legacy version before, you may need some manual migrations.

## Syntax Style Format

The format for syntax style definition has been changed significantly. The user customized styles will be translated automatically to the new style format on the first launch of CotEditor 2. However, we recommend to update or rewrite your styles to conform to the new features for syntax style like the comment-out toggling or new highlighting variations.

You may find some new additional syntax styles on our Wiki page.

## Regular Expression Engine for Outline Extracting

Those who have customized syntax styles in CotEditor 1.x may have to fix their definition to extract outline menu manually, because the regular expression engine for outline parsing has been changed in 2.0 from Oniguruma to ICU library. Validate your customized syntax styles in syntax style editor and follow the messages.

The typical points to fix are:

- The “`{`” and “`}`” as character must always be escaped with backslash “`\`” in ICU, however not in Oniguruma.
- The definition of “`$&`” for the whole matched string was removed in 2.0. Use “`$0`” instead to get the same effect.

See “Use the regular expression” for all regex syntax.

## API for AppleScript

Some specifications for scripting support have been updated on CotEditor 2.0. From this, some user scripts may not run correctly on 2.0 without modifying. See “Script CotEditor with AppleScript” for details of this specification change.

## Bundle Identifier

The bundle identifier for CotEditor was changed from “com.aynimac.CotEditor” to “com.coteditor.CotEditor”. From this change, file mappings or other links to CotEditor (e.g., external editor) outside CotEditor can be reset. Please link them again, if links are lost.

For advanced users: Notice that the filenames for preferences and the domain name for “`defaults`” command in Terminal was also changed.

## See also

- What’s new in CotEditor 2.0?
- Important changes on CotEditor 2.2
- Release notes