Release Designations Defined

Cisco Software
Release Designations Defined 
From:  http://www.cisco.com/public/library/iosplanner/reldesignation.html

• Deferral (DF) 
• Early Deployment (ED) Software releases that provide new features and new platform support in addition to bug fixes. 
• Maintenance Deployment (MD) A Cisco software release that provides bug fix support and ongoing software maintenance. 
• General Deployment (GD)
  Date at which this software release reached the "General Deployment" milestone in its lifecycle. information:http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps6968/ps6350/product_bulletin_cisco_ios_software_gd_program_retirement.html.
• Limited Deployment (LD) A Major Release of Cisco IOS software is said to be in the "Limited Deployment"...
  information:http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps6968/ps6350/product_bulletin_cisco_ios_software_gd_program_retirement.html.