...
Create Linked Issue post function: Now it's possible, that the end user can choose the target project and/or issue type for the new issue!
Basically, as Jira admin, you defined a custom field on the transition screen, which will control the target project/issue type. For example, you might use a Project Picker for this, or a Select List with only a few pre-configured projects.
Improvements
Linked Status validator allows setting custom error message
...