This is thread is not specifically about this page, but about the many subpages it has (one for each X.Y release; e.g., Release notes/1.22). It would be helpful to include in each version section the date that it was originally released.
Include release dates in release notes
I aggree it would be an interesting information on these pages. I just collected some data about the releases, so now these informations can be found in a central page, although this page is a bit heavy and difficult to read; and they could be used to write down the important dates on the release notes pages.