Obsolete No longer available NOTE This might be because of the lack of availability of - Service provision - Support of software production by the original component manufacturer and there is no replacement available processed material supply ORB Obsolescence Review Board proactive strategy development and implementation of an obsolescence management plan in advance reactive strategy reaction to problems of obsolescence as and when they occur Software Obsolescence Software obsolescence results from changes in demands that make it unsuitable for new requirements coming from changes in hardware or additional functional requirements. The issues leading to software obsolescence are described in detail in IEC 62402, first edition 2007-06, chapter 9.1. STC Special Terms and Conditions TRD Technical Requirements Document BT Bombardier Transportation