The Airwave upgrade process to 7.2.3, 7.2.4, or 7.2.5 can fail during the compatibility check with the following error (see upgrade log):
make: Entering directory `/root/svn/mercury'
Can't use an undefined value as a symbol reference at /opt/airwave/local/lib/perl5/site_perl/5.10.0/i386
make: *** [check_visualrf_nav_widgets] Error 2
make: Leaving directory `/root/svn/mercury'
The upgrade halts because it fails a visualrf check when the campus background image is detected missing.
Workaround: If we load any arbitrary image as the campus background the upgrade completes successfully.
This should only affect upgrades to 7.2.3, 7.2.4, and 7.2.5 as the new check was introduced in 7.2.3.