New features
Assemblies
Several improvements have been made to Assemblies, such as:
- Add members to assemblies. #3008
 - An assembly member can be related to an existing user. #3302
 - Show the assemblies that a user belongs to in their profile. #3410
 


Meetings
Meetings have also been improved, regarding the management of collaborative minutes
- Add organizer to meeting and meeting types #3136
 - Add Minutes entity to manage Minutes. #3213
 - Add Agenda and Agenda Item entities to manage meeting agenda. #3305
 

Administration
- Links to participatory space index & show pages from the admin dashboard. #3325
 - Add autocomplete field with customizable url to fetch results. #3301
 - Add endpoint to query organization users in json format. #3381
 
Design
Components and Spaces cards have been redesigned, with a standardised and improved look according to new features.
- New user profile design #3415
 - Add consultation card #3487
 - Add project card #3454
 - Add blog post card #3487
 - Add user profile card #3444
 - Update existing card layout for:
 
Search
- Added a global search engine for Proposals and Meetings. #3559
 
Improvements to existing features
- Render documents in first place. #2977
 - Open attachments in new tab #3245
 - Open space hashtags in new tab #3246
 - Fine grained permissions for: proposals, accountability, budgets, pages, debates, comments, surveys, meetings, sortitions #3029
 - Improve overall navigation of Consultations #3524
 - Let comments have paragraphs to increase readability #3538
 - Sessions expire in one week by default. #3586
 
Fixed
- Enforce permissions when managing meeting minutes. #3560
 - Fix Non private users can participate to a private, transparent assembly #3438
 - Add validation to nickname's length. #3342
 - Deactivate notifications bell when marking all as read #3509
 - Do not allow users to follow themselves #3536
 - Warn the user the attachment is lost when the form for Proposals is errored #3553
 - Make process moderators receive notifications about flagged content #3605
 
Full Changelog: https://github.com/decidim/decidim/blob/0.12-stable/CHANGELOG.md