Hi, I have just found this guide: https://docs.onedev.io/tutorials/issue/default-assignee and it works as expected. So part of my question is already solved.

Now, I am still looking for a solution to get notification in case of an empty Assignee field.

Just subscribe to an issue query. For instance I subscribe to all issues opened:

Thank you for response. But this approach is not a good solution for us.

We have 334 projects imported from YouTrack and GitHub. We are slowly going through all of them to make sure owners/admins are set correctly and all other settings. But this takes time, especially that we have to do our normal development work.

In the meantime, community users already started their activity on the projects migrated to 1dev. They submit new issues. I would like to make sure we did not miss anything new posted to the projects, even if the project is not fully configured yet and/or an issue has an empty Assignee.

So, is there anyway, to send an email notification for any new issue to the project owner, even if the Assignee is empty?

Actually, I have just noticed I can subscribe to All issues for all projects. This is a working temp solution. But it would be better if we could send notifications to the project owner.

This can be achieved with below approach:

1. define a groovy script "watch_issues_for_project_owners":

import io.onedev.server.OneDev
import io.onedev.server.persistence.dao.Dao
import io.onedev.server.persistence.SessionManager
import io.onedev.server.model.*
	
def sessionManager = OneDev.getInstance(SessionManager.class);
sessionManager.openSession();
try {
	for (user in OneDev.getInstance(Dao.class).query(User.class)) {
		for (authorization in user.projectAuthorizations) {
			if (authorization.role.owner) {
				def personalizationOfProject = null;
				for (personalization in user.issueQueryPersonalizations) {
					if (personalization.project.equals(authorization.project)) {
						personalizationOfProject = personalization;
						break;
					}
				}
				if (personalizationOfProject == null) {
					personalizationOfProject = new IssueQueryPersonalization();
					personalizationOfProject.project = authorization.project;
					personalizationOfProject.user = user;
				}
				personalizationOfProject.queryWatchSupport.queryWatches.put("g:All", true);
				OneDev.getInstance(Dao.class).persist(personalizationOfProject);
			}
		}
	}
} finally {
	sessionManager.closeSession();
}

2. Create a ci job in any project to call this script. This can be done by adding a command build step simply running command @script:watch_issues_for_project_owners@