New date not written in series of symbols (7)

I believe the answer is:

notated

I'm a little stuck... Click here to teach me more about this clue!

'written in series of symbols' is the definition.
I can't judge whether this definition defines the answer.

'new date not' is the wordplay.
'new' indicates an anagram.
'date'+'not'='datenot'
'datenot' anagrammed gives 'NOTATED'.

Can you help me to learn more?

(Other definitions for notated that I've seen before include "Set down in symbols" , "symbolically portrayed" , "Marked" , "wrote music?" , "commented on" .)

I've seen this clue in The Independent.

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