I just installed Linux Mint on a new computer, and when I want to install software with apt-get, it always gets obsolete versions. For instance it installs OCaml 4.01.0 (latest is 4.02.3) and Opam 184.108.40.206 (latest is 1.2)
It is the same in Synaptic.
How can I install the latest versions ? If possible without doing manually, as I'm not at ease with Linux and would prefer the automatic option for now.