Worker unhappy about edition that's passed on (6,4)

'passed on' is the definition.
(handing down is a kind of passing on)

'worker unhappy about edition' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker).
'unhappy' becomes 'down' (I've seen this before**).
'about' says to put letters next to each other.
'edition' becomes 'ed'.
'down' put after 'ed' is 'eddown'.
'hand'+'eddown'='HANDED-DOWN'

'that's' is the link.