Why nginx gzip_http_version defaults to HTTP 1.1

Question

The default value for gzip_http_version setting in nginx's gzip module is HTTP 1.1. Why? Is there any problem with using gzip and HTTP 1.0?

Answer 1

nginx gzip_http_version can have HTTP 1.0 and has it's caveats.

When HTTP version 1.0 is used, the Vary: Accept-Encoding header is not set. As
this can lead to proxy cache corruption, consider adding it with add_header.
Also note that the Content-Length header is not set when using either version.
Keepalives will therefore be impossible with version 1.0, while for 1.1 it is
handled by chunked transfers.  

More here -- http://wiki.nginx.org/HttpGzipModule

Answer 2

It's most probably because HTTP 1.1 is the current version. There is little sense in defaulting to the previous version if the current verison is well adopted.