2.3 reached EOL in 2013-06-25 when rails 4.0.0 was released.
Only the "last major release series" will receive patches, according to Michael Kozyarski . Therefore, when 4.0 was released, 2.3 stopped receiving fixes.
The rails team hoped to give up support much earlier. In 2011-12-29, Aaron said :
.. we do not plan to release another version 2.3 [for 2.3.14]
Prior to this, in 2011-06-08, Aaron said :
This branch [2.3] is in security mode. We will release it when problems arise, such as โthe sky is fallingโ or major security issues. It's time to focus on moving Rails forward!
source share