Current news:

Catholic News Service: Pope revises catechism to say death penalty is 'inadmissible'

British Broadcasting Corporation: Pope Francis declares death penalty inadmissible in all cases

Australian Broadcasting Corporation: Pope Francis changes teachings to oppose death penalty in all cases

New York Times: Pope Declares Death Penalty Inadmissible in All Cases

The lead-up:

CNN (3 years ago): Death penalty showdown: The Pope vs. the Supreme Court

America: The Jesuit Review of Faith & Culture
(1 year ago): Pope Francis: The death penalty is contrary to the Gospel

And... a contrary opinion from The Catholic World Report one year ago: Why the Church Cannot Reverse Past Teaching on Capital Punishment