Question

what is the 'update'

Answer 1

make (something) more modern or up to date.
"security measures are continually updated and improved"
synonyms: modernize, bring up to date, bring into the twenty-first century, renovate, refurbish, recondition, overhaul, re-equip, improve, better, upgrade, streamline, rationalize, reform, revise, correct, amend; bring up to code
"security measures are continually updated"

Answer 2

the update we done in computer and mobile.
the update is a software file that contains files for problems found by other users