Dont seem to be able to get xenology anymore
#How do you get ciphers anymore?
broken relic
elfin sapphire
xur sells them on occasion. also resetting xur's or rahool's reputation gives one
xenology also only appears if you haven't completed the quest that week, even if you got it from a previous week. so if you picked it up last week and turned it in this week, he won't sell it until next week
light ravine
Xur page 2