is it okay for nginx to send an http/1.1 response even though backend responded with http/1.0

[Yusuf Goolamabbas]

Hi, I am curious if the above behaviour is okay as per the RFC. I
verified this behaviour by conifguring a backend lighttpd to send out
http/1.0 response via the following config

server.protocol-http11 = "disable"

nginx reverse proxying this however continues to respond with a
http/1.1 to the end client as evident

I am not sure if the RFC allows for this

http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.1

I'm okay if this were configurable