Release version of song for two barely behind schedule (7)
I believe the answer is:
overdue
'behind schedule' is the definition.
(I've seen this before)
'release version of song for two' is the wordplay.
'release' is an anagram indicator (I've seen 'released' mean this (letters released from their original order)).
'version' becomes 'v' (ve, vr etc).
'of' becomes 'o''.
'song for' becomes 'er' (I can't justify this - if you can you should give a lot more credence to this answer).
'two' becomes 'due' (I've seen this in another clue).
'v'+'o'='vo'
'vo' with letters rearranged gives 'ov'.
'ov'+'er'+'due'='OVERDUE'
'barely' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for overdue that I've seen before include "(Of library books) late" , "Still unpaid" , "Do revue after the appointed time" , "Not having arrived at the expected time" , "Later than the appointed time, as for bill payment" .)