Announcing Mirador 4.0

[Enrique Diaz]

Hello!

The community of Mirador contributors is excited to announce the release of Mirador 4.0, a configurable, extensible, and easy-to-integrate image viewer, enabling image annotation and comparison of images that support the International Image Interoperability Framework (IIIF) APIs. 

Mirador 4 is a massive modernization of the 3.3 codebase, with updates to the virtual entirety of its upstream dependencies. This effort also introduced improvements to the user interface, accessibility, internationalization, IIIF support, and the developer experience.

 For Mirador Developers

Because Mirador 4.0 updated downstream application use to React 19 and Material UI (MUI) 7, it includes breaking changes and significant architectural refactoring. Upgrading from Mirador 3.x or earlier requires updates to custom plugins, integrations, or theming. Top-level things to be aware of include:

• The upgrade from React 16 to version 19 required significant changes to core application behaviors due to fundamentally new or different methods and functions.
• The testing suite has been replaced with React Test Library (RTL) and all tests have been rewritten.
• The upgrade from MUI 4 to 7 required significant changes to class names and selectors corresponding to global interface elements.
• Emotion replaces JSS as Mirador's styling engine.
• Plugins no longer offer UMD build options, only ES. Use vite to integrate the ES version of the packages.
• Most functions and components are now exposed at the top level, requiring imports.
  
  

Developers are strongly encouraged to read through the Mirador 4.0 Release Notes for detailed descriptions of changes and links to upgrade guides referenced by core contributors in the course of update work.

Additionally, the Mirador Integration Github repository has been updated for 4.0. This resource gives concrete examples of how to work with Mirador, from initializing the viewer to including and writing Mirador plugins. This resource is useful for experienced Mirador developers and newcomers alike.

 Plugin Support

Alongside core Mirador work, contributors also fully updated a set of plugins for compatibility with 4.0. These include:

• mirador-image-tools 
• mirador-dl-plugin 
• mirador-share-plugin 
  
  

Prioritization of these plugins was largely informed by a survey organized and conducted by community members in 2024. If you participated in that survey, thank you! Your input helped get these through foremost.

A Special Note About the Annotations Plugin

Core contributors are presently discussing a fundamental rewrite of mirador-annotations to leverage newer components to support annotations. In the meantime, the team behind the NumaHOP platform let us know about the availability of their Mirador Thumbnail Annotation Plugin, a fork of the original plugin that they’ve updated. It has been verified as compatible with Mirador 4.0 and can be incorporated in builds right away. Also, Tétras Libre recently announced their Mirador Annotation Editor Plugin has been updated for 4.0 compatibility. 

 The Road Ahead

Throughout the course of this update, attendees of the bi-weekly Mirador Community Calls have helped shape what near-term next steps for Mirador’s development should focus on. Upcoming work includes:

• additional plugin updates for 4.0 compatibility
• reviewing documentation to improve contributor support
• improving interface digital accessibility and user experience based on contemporary research and standards
• incorporating support for the IIIF Authorization Flow 2.0 specification
• additional architectural improvements
  
  

Anyone with affinities or institutional goals aligned similarly to what’s listed above is warmly invited to get involved. Information about how can be found below.

 Acknowledgements

This release is the culmination of a multi-year, multi-institution effort, with great time, care, and attention generously provided by developers and technologists around the world. Special thanks are especially owed to the teams at Stanford University, Universität Leipzig, Harvard University, the Canadian Knowledge Research Network, Columbia University, New York University, and Université de Rennes. Appreciation also goes to all the individuals who assisted with reviewing release candidates, responding to community surveys, and participating in Community Calls. It is a clear testament to the strength and value of collaborative, community software development.

 Contributors Welcome

Whether you're a first-time contributor or a seasoned expert, we encourage you to join us to help make Mirador better for users around the globe.

• Community Calls

Calls take place every other Thursday at 8am PST / 11am EST / 4pm GST over Zoom. All are welcome to add topics to upcoming call agendas and join the group for discussions.  

• Slack

Join us on the #mirador and #mirador-dev channels in the IIIF Slack workspace.

Thank you,

Enrique Diaz, on behalf of the Mirador Community

— 

Enrique A. Diaz 
Manager, Architecture & Engineering for Discovery | Library Technology Services 
Harvard University Information Technology 
W: library.harvard.edu | huit.harvard.edu 
(he / him / his)