Ubuntu 12.04 EOL appears in motd after release upgrade to 14.04 [duplicate]
/etc/update-motd.d/99-esm contains the undying message/advertisement. This file was created on April 28, 2017, which is the day that 12.04 went End Of Life.
Deleting /etc/update-motd.d/99-esm and /run/motd.dynamic will cause a refresh of motd.dynamic the next time someone logs in.