Form of AI no longer fresh, surely lacking core support (6,6)

I believe the answer is:

expert system

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'form of ai no longer' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'fresh surely lacking core support' is the wordplay.
'fresh' becomes 'expert' (I can't explain this - if you can you should believe this answer much more).
'lacking core' says to hollow out the word (remove centre letters).
'support' becomes 'stem' (I've seen this before).
'surely' with its middle taken out is 'sy'.
'expert'+'sy'+'stem'='EXPERT SYSTEM'

Can you help me to learn more?

(Another definition for expert system that I've seen is " Software using knowledge database for decisions".)

I've seen this clue in The Times.

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