# Migrating to release 4.1

DITA-OT 4.1 includes a new version of the Lightweight DITA plug-in with significant enhancements to Markdown processing, and updates for the latest DITA 2.0 draft standard.

Note:
This topic provides a summary of changes in DITA-OT 4.1 that may require modifications to custom stylesheets or plug-ins. For more information on changes in this release, see the DITA-OT 4.1 Release Notes.

## Legacy `<tt>` style attributes moved to CSS

The HTML5 plug-in has been updated to remove the remaining inline style attributes that prevented custom plug-ins from overriding the monospace font presentation of teletype `<tt>` elements.

These changes move the default teletype styling to CSS to allow users to override the presentation in custom stylesheets. The output is visually equivalent to the results generated by previous toolkit versions.

Important:
In publishing environments that do not use the default CSS files, these styles may need to be implemented in custom stylesheets.