How to Remove Client Headers in Nginx before passing request to upstream server?
The proxy_set_header HEADER “” does exactly what you expect. See https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_set_header. If the value of a header field is an empty string then this field will not be passed to a proxied server: proxy_set_header Accept-Encoding “”; I have just confirmed this is working as documented, I used Nginx v1.12.