[LAU] Which jackd to install on a new system ?

[jonetsu]

Finally installed a new system, Linux Mint 18, based on Ubuntu.  I am
not sure therefore I ask, it seems there are two parallel versions of
jack being developed or in the least,m there are two of them out there
which could, or could not be candidate for installation, possibly known
as jackd and jackd2. If there's only one, then all right.  In any case,
which jackd should be installed on a 2017 brand new 64-bit system ?  

Thanks.