Changes with nginx 1.17.1 25 Jun 2019
*) Feature: the "limit_req_dry_run" directive.
*) Feature: when using the "hash" directive inside the "upstream" block an empty hash key now triggers round-robin balancing. Thanks to Niklas Keller.
*) Bugfix: a segmentation fault might occur in a worker process if caching was used along with the "image_filter" directive, and errors with code 415 were redirected with the "error_page" directive; the bug had appeared in 1.11.10.
*) Bugfix: a segmentation fault might occur in a worker process if embedded perl was used; the bug had appeared in 1.7.3.