How to upgrade the NIS if the upgrade is available?
Get latest package from bob.nem.ninja.
Latest one is https://bob.nem.ninja/nis-0.6.97.tgz
So we need to install it again? Then node will start syncing again from 1st block? or from the old block?
Just: stop node, replace package and start. Synced blockchain is stored in seperate directory (home/nem/nis by default)