That page has the release notes for 3.8, that is the most recent version.
Where it says "since version 3.7.1"... well, read the quoted text better.
Still don't understand?
"since version 3.7.1" means these features are the features added from 3.7.1 to 3.8. So, the listed features are the ones added in 3.8, if that's what you were looking for.
Do you understand now?