We are pleased to announce the development release of ROOT version 5.23/02. For the list of improvements, see the release notes and additional information at root.cern.ch.
Rene Brun on behalf of the ROOT team.
The link to release notes it for “Version 5.24 Release Notes”. 
This is correct. dev 5.23 will be released as pro version 5.24 in June.
I know that this might look incoherent with the dev notes, but they are generated automatically by scripts and I do not want to change this machinery.
Rene