One upgrade tentatively settled (6,4)

I believe the answer is:

agreed upon

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

'settled' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?

'one upgrade tentatively' is the wordplay.
'tentatively' is an anagram indicator.
'one'+'upgrade'='oneupgrade'
'oneupgrade' with letters rearranged gives 'AGREED UPON'.

Can you help me to learn more?

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.