WordNet records no synonym and no antonym for update. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
modernize or bring up to date
“We updated the kitchen in the old house”
bring up to date; supply with recent information
bring to the latest state of technology or supply with the latest data
“tonight, I will update my operating system”
Synonyms, antonyms and the broader and narrower relations for update come from Princeton University’s WordNet. Full sources and licences.
information or data that updates
“do you have the latest software update?”
the act of bringing someone or something up to date
“the server update ran overnight”