Haven, old, unchanged (5)
I believe the answer is:
oasis
'haven' is the definition.
(I know that haven can be written as oasis)
'old unchanged' is the wordplay.
'old' becomes 'o' (abbreviation).
'unchanged' becomes 'as is' (as things currently are).
'o'+'asis'='OASIS'
(Other definitions for oasis that I've seen before include "quiet spot" , "place of relief" , "British band" , "Q-and-A game" , "Place of peace" .)