Bug#863864: release-notes: Document that nagios is not in stretch and how to switch to icinga (if that is possible)

[Johannes Ranke <jranke@uni-bremen.de>]

Package: release-notes
Severity: normal

I assume that switching to icinga is possible, but I am missing a hint in the
release notes. Will icinga use nagios configuration files?


-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64
 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-3-amd64 (SMP w/8 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)