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If you are expanding from a few projects to a larger number of projects within the same group, you may want to share the same milestone among multiple projects in the same group. If you previously created a project milestone and now want to make it available for other projects within the same group, you can promote it to a group milestone.
From the project milestone list page, you can promote a project milestone to a group milestone. This will merge all project milestones across all projects in this group with the same name into a single group milestones. All issues and merge requests that previously were assigned one of these project milestones will now be assigned the new group milestones. This action cannot be reversed and the changes are permanent.
From GitLab 12.4 and earlier, some information is lost when you promote a project milestone to a group milestone. Not all features on the project milestone view are available on the group milestone view. If you promote a project milestone to a group milestone, you will lose these features. See [Milestone view](#milestone-view) to see which features are missing from the group milestone view.
Every issue and merge request can be assigned a milestone. The milestones are visible on every issue and merge request page, in the sidebar. They are also visible in the issue board. From the sidebar, you can assign or unassign a milestones to the object. You can also perform this as a [quick action](../quick_actions.md) in a comment. [As mentioned](#project-milestones-and-group-milestones), for a given issue or merge request, both project milestones and group milestones can be selected and assigned to the object.
## Filtering issues and merge requests by milestone
### Filtering in list pages
From the project issue/merge request list pages and the group issue/merge request list pages, you can [filter](../../search/index.md#issues-and-merge-requests) by both group milestones and project milestones.
- From [project issue boards](../issue_board.md), you can filter by both group milestones and project milestones in the [search and filter bar](../../search/index.md#issue-boards).
- From [group issue boards](../issue_board.md#group-issue-boards-premium), you can filter by only group milestones in the [search and filter bar](../../search/index.md#issue-boards). **(PREMIUM)**
- From [project issue boards](../issue_board.md), you can filter by both group milestones and project milestones in the [issue board configuration](../issue_board.md#configurable-issue-boards-starter). **(STARTER)**
- From [group issue boards](../issue_board.md#group-issue-boards-premium) you can filter by only group milestones in the [issue board configuration](../issue_board.md#configurable-issue-boards-starter). **(STARTER)**
- **Upcoming**: Show issues or merge requests that have been assigned the open milestone that has the next upcoming due date (i.e. nearest due date in the future).
For project milestones in [GitLab Starter](https://about.gitlab.com/pricing/), a [burndown chart](burndown_charts.md) is in the milestone view, showing the progress of completing a milestone.
For group milestones in [GitLab Premium](https://about.gitlab.com/pricing/), a [burndown chart](burndown_charts.md) is in the milestone view, showing the progress of completing a milestone.