Changes with nginx 1.19.7 16 Feb 2021
*) Change: connections handling in HTTP/2 has been changed to better match HTTP/1.x; the "http2_recv_timeout", "http2_idle_timeout", and "http2_max_requests" directives have been removed, the "keepalive_timeout" and "keepalive_requests" directives should be used instead.
*) Change: the "http2_max_field_size" and "http2_max_header_size" directives have been removed, the "large_client_header_buffers" directive should be used instead.
*) Feature: now, if free worker connections are exhausted, nginx starts closing not only keepalive connections, but also connections in lingering close.
*) Bugfix: "zero size buf in output" alerts might appear in logs if an upstream server returned an incorrect response during unbuffered proxying; the bug had appeared in 1.19.1.
*) Bugfix: HEAD requests were handled incorrectly if the "return" directive was used with the "image_filter" or "xslt_stylesheet" directives.
*) Bugfix: in the "add_trailer" directive.