Installing IIAB 6.7/master (http://d.iiab.io/6.7) on Debian 10 "Buster" pre-releases can work! With these 3+2 known caveats:

• Ensure the line VERSION_ID="10" (or VERSION_ID="10.0") exists in /etc/os-release. This allows iiab-install to run /opt/iiab/iiab/scripts/local_facts.fact -> /etc/ansible/facts.d/local_facts.fact properly, setting OS_VER to "debian-10" so we're ready for Debian 10's pre-releases in coming months. (Final releases will contain a similar such line by/around mid-2019.)
• The 3 lines in /usr/bin/iiab-refresh-wiki-docs that use lynx to download from github.com (for http://box/info documentation) need to be commented out for now — mysteriously GitHub is blocking all connections from lynx on Debian 10, even when lynx issues exactly the same headers as from Ubuntu/Raspbian or Debian 9! Possibly this is a subtle SSL/TLS problem, even when lynx claims to be using the same SSL as on the other distros?!
• "Stop ejabberd service" froze during ejabberd's install (when installing BIG-sized IIAB) so systemctl stop ejabberd had to be run manually. Installation then continued on its own: relaunching IIAB's install with sudo iiab was not even nec this time!

This/these issue(s) below appear more serious?

• Kolibri 0.11.1 -> 0.12.1 (http://box:8009 -> http://box/kolibri) doesn't seem to work on Debian 10, despite its IIAB install completing without obvious errors — please run cd /opt/iiab/iiab then ./runrole kolibri to help us look more close if you can!
• MongoDB (for Sugarizer) not installable due to missing packages: [Debian 10] MongoDB not installable due to missing packages [for Sugarizer] #1437
  • Workaround implemented, bypassing MongoDB & Sugarizer on Debian 10+ for now: PRs Debian 10: bypass Sugarizer install for now, as MongoDB is unavailable #1850 Fix #1850: Fully bypass Sugarizer (AND MongoDB) on Debian 10+ #1852
• Monit was removed by Debian 10 suddenly, just prior to the OS's 2019-07-06 release: @m-anish & @tim-moody ask: can systemd now replace Monit? [Debian 10 Buster no longer includes Monit] #1849
  • Workaround implemented, to bypass Monit on Debian 10+: PR Ugly workaround so that IIAB installs on Debian 10 Buster (which suddenly removed monit) #1842

Ref: PR #1386, PR #1435, #1436