Login via action=login was deprecated in rMW54d58ef50665: API changes for AuthManager, which landed Jan 11 2016
Password for user xxxxxxx on wiktionary:xxx (no characters will be shown): Logging in to wiktionary:xxx as xxxxxxx WARNING: API warning (login): Main-account login via action=login is deprecated and may stop working without warning. To continue login with action=login, see [[Special:BotPasswords]]. To safely continue using main-account login, see action=clientlogin.