Updating a review paper after several years by publishing a new review paper

Updated review papers are not particularly unusual, as a Google Scholar search readily demonstrates. You should definitely explicitly declare the paper as an updated review, and it is probably best to send the paper to the same journal as before. If you can get in touch with the journal editors, they may even be able to expedite the review process, since they already know and have accepted the first version.

This is a stunningly common occurrence in medicine. See the Cochrane library for a myriad of examples. Many of the reviews in there have pre-planned revision dates as well.