Since you already have 15.6, the easiest way (from my experience) is a distribution upgrade with “zypper dup”, as described in this post: Serious mess when upgrading select machines from 15.6 to 16.0 - similar thread - #11 by ks25.
Since you already have 15.6, the easiest way (from my experience) is a distribution upgrade with “zypper dup”, as described in this post: Serious mess when upgrading select machines from 15.6 to 16.0 - similar thread - #11 by ks25.