Since 7.2.0 the RPM packages are not signed and yum complains:

yum -y update
Loaded plugins: fastestmirror, langpacks, versionlock
Loading mirror speeds from cached hostfile

* base: ftp.plusline.de
* epel: mirror.imt-systems.com
* extras: ftp.plusline.de
* updates: ftp.plusline.de
Resolving Dependencies
—\> Running transaction check
—-\> Package openproject.x86\_64 0:7.1.0-1499089014.b01cc3e.centos7 will be updated
—-\> Package openproject.x86\_64 0:7.2.1-1502886342.7c2a83f0.centos7 will be an update
—\> Finished Dependency Resolution

Dependencies Resolved

\=
Package Arch Version Repository Size
\=
Updating:
openproject x86\_64 7.2.1-1502886342.7c2a83f0.centos7 openproject 125 M

Transaction Summary
\===
Upgrade 1 Package

Total size: 125 M
Downloading packages:

Package openproject-7.2.1-1502886342.7c2a83f0.centos7.x86\_64.rpm is not signed Begin of the insertion
End of the insertion