The Dolet® for Sibelius plug-in exports MusicXML files from the Sibelius Ultimate application. It works with Sibelius Ultimate version 2019.5 and later. Instructions for installing and using the plug-in are contained in the Dolet8Readme.html file.
This open source plug-in is available under the MIT license provided in the LICENSE file. MakeMusic provides this repository for the convenience of open source developers, but does not maintain or support the plug-in.