In some Cisco equipment you may run into a common error when installing a 3rd party transceiver.  Here is an example of what will be displayed...

System Cisco Nexus 7000 Series Software Versions  Release 6.2.8 Issue 3rd Party SFP/SFP+ reported as "U...

System   Cisco MDS 9000 Series Multilayer Switches. Specifically seen in MDS 9148   Software Versions  Currently known influential versions are 8.1(...