Dark times — but things have altered (6)
I believe the answer is:
nights
'dark times' is the definition.
(I've seen this in another clue)
'things have altered' is the wordplay.
'things' can be anagrammed to 'NIGHTS'.
Though, I am unsure how the anagram is indicated.
'but' is the link.
Can you help me to learn more?
(Other definitions for nights that I've seen before include "Periods after sunset" , "Times after sunset" , "Things (anag.)" , "dark times" , "Times of darkness" .)