As a user, I'd like to be able to update issues using JSON file.

Currently, the external system import allows only to create new issues when using the JSON input method.
But, it would be good to be able to update issues as it is possible to set the issue key on the JSON file, with that, it will update only the issues and the specific content specified on the JSON field.

Due to this limitation, when importing issue history or fields and will require to adjust the issue, I have to delete all the issues and import everything again, instead of just updating the issues by setting the correct values from the existing file.