1. AXELOS. (2019). ITIL® Foundation: ITIL 4 Edition. TSO (The Stationery Office).
Section 5.2.11
Portfolio management: "The purpose of the portfolio management practice is to ensure that the organization has the right mix of programmes
projects
products
and services to execute its strategy within its funding and resource constraints." The section further clarifies that this includes decisions to "retire... existing products and services."
2. AXELOS. (2020). ITIL® 4: Direct
Plan and Improve. TSO (The Stationery Office).
Section 4.3.6
Portfolio management: This section describes how portfolio management helps "determine the optimum mix of initiatives to achieve strategic objectives
under the constraints of available resources... It involves reviewing the existing portfolio to identify candidates for improvement
replacement
or retirement."
3. Iden
J.
& Eikebrokk
T. R. (2013). Implementing IT Service Management: A systematic literature review. International Journal of Information Management
33(3)
512-523.
Section 4.2
Portfolio Management: The review highlights that a central tenet of portfolio management is the "evaluation and prioritization of IT investments
" which includes the "decommissioning of legacy systems and services to free up resources for more valuable projects." (DOI: https://doi.org/10.1016/j.ijinfomgt.2013.01.004)