Growth/Newsletters/24


 * New publication period: 6 times a year -- January, March, May, July, September, November.
 * Growth/Personalized first day/Newcomer experience marketing pilot/Welcome emails experiment, September 2022
 * https://phabricator.wikimedia.org/T321500
 * Suggested links deployment update
 * https://phabricator.wikimedia.org/T323038
 * https://phabricator.wikimedia.org/T301096