Back numbers, maybe (6)
I believe the answer is:
issues
'back numbers' is the definition.
'issues' can be an answer for 'numbers' ('issue' can be a synonym of 'number'). I'm not certain of the 'back' bit.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for issues that I've seen before include "Editions or important questions" , "Sends out, or matters of concern" , "Brings out a publication" , "Puts out, a statement perhaps" , "Individual editions" .)