On obsolete tech, management is the barest minimum (5,2,3,4)
I believe the answer is:
close to the bone
'the barest minimum' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'on obsolete tech management' is the wordplay.
'management' indicates an anagram.
'on'+'obsolete'+'tech'='onobsoletetech'
'onobsoletetech' with letters rearranged gives 'CLOSE TO THE BONE'.
'is' is the link.
Can you help me to learn more?
(Other definitions for close to the bone that I've seen before include "Naughty" , "like an intense osteologist?" , "Almost offensive" , "likely to cause offence" , "Where some body parts are" .)