I am using Linux mint with windows 10 in dual boot. For sometime now,I have been away from Linux boot. How can I verify whether my Linux is the latest one?
If you mean a full upgrade to a new version of Mint:
mintupgrade tool. If it's not already installed on your Mint system, you'll need to install it,
apt-get install mintupgrade.
Then you can run
mintupgrade check to see if any upgrades are available, and
mintupgrade upgrade to perform the upgrade (if an upgrade is available).
Otherwise, if you just mean updating the packages in your current Mint version to the latest packages for that version, it can be updated like Ubuntu, with
apt-get update to refresh the packages available from the repos, and
apt-get upgrade to install any upgrades that are available.