Replace deprecated REST API used on create issue -
Not required at this time, but there is an admin option on 8.4 to turn off the use of the old API. If used on your instance, clients must upgrade to 9.0 or higher otherwise createIssue actions will break. It is more likely larger data center instances may choose to turn the old APIs off.
Issue creator no longer automatically added to watch list by Jira - no impact to CLI, but impacts testing or scripts that may rely on that (Cloud still does add).