==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):
0.9.7, as I read that this is the last version that supports Debian 8 (Jessie) here: https://www.bentasker.co.uk/documentati … n-jessie-8
- Deployed with iRedMail Easy or the downloadable installer?
downloadable
- Linux/BSD distribution name and version:
Debian 8 (Jessie)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
PGSQL
- Web server (Apache or Nginx):
Nginx
- Manage mail accounts with iRedAdmin-Pro?
Not there yet.
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
WARNING: The following packages cannot be authenticated!
  nginx nginx-common libnginx-mod-http-auth-pam libnginx-mod-http-dav-ext
  libnginx-mod-http-echo libnginx-mod-http-geoip
  libnginx-mod-http-image-filter libnginx-mod-http-subs-filter
  libnginx-mod-http-upstream-fair libnginx-mod-http-xslt-filter
  libnginx-mod-mail libnginx-mod-stream libssl1.0.0 nginx-full libpq-dev
  libpq5 librpmio3 debugedit dovecot-core dovecot-imapd dovecot-lmtpd
  dovecot-sieve dovecot-managesieved dovecot-pgsql dovecot-pop3d librpm3
  librpmbuild3 librpmsign3 postgresql-client-common postgresql-client-9.6
  postgresql-common postgresql-9.6 postgresql postgresql-client
  postgresql-contrib-9.6 postgresql-contrib python-jinja2 python-pyinotify
  python-sqlalchemy python-sqlalchemy-ext rpm-common rpm2cpio rpm
E: There are problems and -y was used without --force-yes
<< ERROR >> Installation failed, please check the terminal output.
<< ERROR >> If you're not sure what the problem is, try to get help in iRedMail
<< ERROR >> forum: http://www.iredmail.org/forum/
====

Hi all! I'm sorry if this is a stupid question/issue... I consider myself a noob. Mea culpa.

But when I'm running the installer of 0.9.7 on my Debian 8 (Jessie) box, I get the aforementioned error.
As mentioned above, I'm installing this version as I understood that this was the last to support Debian 8.

I'm pretty sure I understand what's wrong, but I'm not sure how to fix this.
I found a couple of old posts on this and understand that I should attempt to get the right app keys, but not sure for which and how.

I should confess that this is not a fresh installation (although it's pretty obvious by now).
If someone could help point me in the right direction, that would be great.
If I should just upgrade Debian and stop trying to install older iRedMail versions, I would understand that too...