The Upgrade header field is an HTTP header field introduced in HTTP/1.1. In the exchange the client begins by making a cleartext request which is later upgraded to a newer HTTP protocol version or switched to a different protocol.
Websites using header upgrade | 6,881,380 |
Percentage of websites that use upgrade header | 8.52% |
Total discovered header values | 134 |
Header uses directives | No |
Header values are unique or random | No |
Most popular in the country | United States |
Directive | Share | Websites count | Unique Values |
---|
HTTP/2, category Miscellaneous, total 6,882,027 websites |
Domain | Country | Rank | Contacts |
---|---|---|---|
simcast.com | Singapore | 105 | |
caniuse.com | United States | 288 | |
ncbi.nlm.nih.gov | United States | 299 | |
www.ncbi.nlm.nih.gov | United States | 299 | |
serenemedia.co.uk | GB | 530 | |
dg-datenschutz.de | Germany | 570 |
Header value | Value prevalence |
---|---|
h2,h2c | 77.41% |
h2 | 21.26% |
h2c | 1.07% |
h2c,h2 | 0.22% |
h2,http:/1.1 | 0.02% |
acme-tls/1 | 0.00% |
websocket | 0.00% |
h2,h2c,http:/1.1 | 0.00% |
h2,h2c,http/1 | 0.00% |
h2,HTTP,1.1 | 0.00% |
h2,Http/1.1 | 0.00% |
HTTP/1.1 | 0.00% |
h2,http/1.0 | 0.00% |
h2,h2c,HTTP/1.1 | 0.00% |
TLS/1.2, HTTP/1.1 | 0.00% |
h2,h2c,h2-14 | 0.00% |
h2,h2c,http,/,1.1 | 0.00% |
h2,http1/1 | 0.00% |
http:/1.1 | 0.00% |
h2,hc2 | 0.00% |