A systematic review already exists in the literature. When is a newer one required?
When? 


Whenever there is a set of papers that has significantly extended or changed the topic of interest.
If you have to do it as part of your thesis.
If you are contributing with a new approach/method in a publication (the literature review would typically be part of the Introduction).


My advice: do not spend too much time on writing and trying to publish a literature review if the problem has not evolved significantly during this time. Most of this kind of works get lost in an ocean of surveys.