Receiving Signature Check errors trying to install GroupWise on SLES 12 SP2 server

Unable to install GroupWise after installing updates on SLES 12 SP2 server
The install fails at the start with the following errors:  "Package is not signed!" "Signature verification failed" "gw-oracle-outside-in-8.5.3-3.x86_64"
Installing GroupWise onto SLES12 SP2 getting package not signed error message and terminates the installation

1. Disable package gpgcheck in zypp.conf
   
   • Navigate to /etc/zypp/
   • Open the zypp.conf and locate the following line # pkg_gpgcheck =  unset -> according to gpgcheck
     
   • Copy this line or uncomment by removing the # and change/add text to the following: pkg_gpgcheck = off
   • Save and exit the file
2. Run the GroupWise install.sh once again.  This time it should not do the package gpgcheck and bypass signature errors

This has also been resolved in GroupWise 18

An update on July 17 2017 enforces zypper to report unsigned packages which prevents the install from proceeding

Changelog entry for update that causes this issue in most recent cases observed:

* Mon Jul 17 2017 ma@suse.de
- PackageProvider: enforce a signed package if pkgGpgCheckIsMandatory
- Add RpmDb::checkPackageSignature to report unsigned packages
- Fix repo gpg check workflows, mainly for unsigned repos and packages
  (bsc#1045735, bsc#1038984, CVE-2017-7435, CVE-2017-7436, CVE-2017-9269)
- version 16.15.0 (0)