Application Decommissioning the Right Way: A Complete Guide for 2026

Legacy systems don’t just sit quietly in the background. They drain IT budgets, expose hidden compliance risks, and slow down every modernization effort your organization makes. The numbers are not unknown to the CIOs and IT leaders: up to 70% of IT budgets are consumed by maintaining legacy applications that no longer support growth.

The risks go deeper than just the cost. These unsupported applications leave compliance gaps, make security incidents harder to contain, and forces organizations to keep paying for systems they’d rather move past.

In regulated sectors like healthcare, finance, and manufacturing, the challenge is even sharper: auditors still want access to historical data, even if the application that created it is long past its prime. So, they keep paying millions just to “keep the lights on” in old, applications.

This is where application decommissioning and application retirement comes in. It frees organizations from legacy systems while preserving access to historical data for audits, analytics, and governance.

In this guide, we’ll explore the difference between retirement and decommissioning, the step-by-step process, benefits, and real-world examples; so, you can retire outdated systems without losing the data your business still relies on.

What is Application Decommissioning

Application decommissioning is the process of shutting down an application while preserving its historical data in a secure, governed archive. This ensures that audits, eDiscovery, and business users can still access what they need, even after the system itself is no longer active.

Examples:

• A hospital decommissions its outdated scheduling system but keeps all appointment history in an archive to meet healthcare regulations.
• A manufacturer retires JD Edwards and archives historical financial data to keep audit trails intact.
• A law firm decommissions Lotus Notes while keeping emails archived for eDiscovery.
• A bank decommissions a legacy loan platform while ensuring auditors can still retrieve 10 years of transaction data.

Application Decommissioning vs Application Retirement vs Sunsetting

Enterprise organizations often use these terms interchangeably, but they represent distinct phases in the application lifecycle with important strategic implications.

Software Sunsetting

It is a planned phase-out or discontinuation of a software product, typically announced with advance notice to users and stakeholders.

Purpose: Strategic business decision to stop selling, developing, or marketing a product while providing transition time

Key Characteristics:

• Advance notification period (typically 6-12 months)
• Migration paths offered to users
• Limited ongoing support during transition
• Often precedes retirement or decommissioning

Application Retirement

The process of ceasing active use of an application while preserving data access for compliance, audit, or business needs.

Purpose: End operational use while maintaining historical data accessibility.

Key Characteristics:

• Read-only access maintained for compliance
• System moves from productive to non-productive status
• Focus on data preservation and regulatory adherence

Application Decommissioning

The systematic and complete removal of outdated applications from the IT environment while ensuring compliant data archiving.

Purpose: Permanent elimination of system infrastructure with secure data transition.

Key Characteristics:

• All system components removed
• Focus on cost elimination and security enhancement

Comprehensive comparison matrix: Application Retirement vs Decommissioning vs Software Sunsetting

How to Define a Legacy System

Not every old application qualifies as “legacy.” A system becomes legacy when it no longer aligns with the business’s needs, instead creates more risks, and drains resources.

Characteristics of legacy systems:

• Over 10 years old or built on outdated technology stacks
• Developed in obsolete languages like COBOL or Fortran
• Costly and difficult to maintain or evolve
• Missing or unreliable documentation
• Dependent on specialized skill sets that are hard to replace
• Unable to support modern business requirements (e.g., mobile access, cloud integration)

When to Decommission a Legacy System

Organizations typically pursue decommissioning for several reasons:

• Cost reduction: Legacy systems consume budgets with licensing fees, support contracts, infrastructure upkeep, and niche skill sets. Studies show inactive application decommissioning can save ~$40,000 per year, while enterprise systems can yield over $120,000 annually.
• Mergers & Acquisitions (M&A): Consolidating overlapping applications after M&A activity often makes certain systems redundant, requiring decommissioning to streamline IT portfolios.
• Vendor end-of-life announcements: When a provider ends support, organizations are forced to decommission or risk compliance and security issues.
• Security enhancement: Outdated systems often lack modern patching and features like MFA, exposing sensitive data to cyber risks.
• Operational efficiency: Old apps fragment data, slow down workflows, and limit agility.
• Compliance requirements: Frameworks like GDPR, HIPAA, and SOX demand retention and audit readiness that legacy systems may not provide.
• Technical obsolescence: Unsupported vendors, outdated operating systems, or integrations that can’t scale.
• Business changes: Cloud-first strategies or rationalizing overlapping systems.
• Regulatory pressure: Industries under strict retention mandates often need to maintain searchable archives of retired systems for long-term accessibility.

Legacy Systems Commonly Decommissioned

Application decommissioning spans multiple platforms, each with unique challenges.

SAP Decommissioning

SAP remains one of the most common decommissioning scenarios, with enterprises facing the end of support for older platforms.

• SAP S/4HANA – As organizations migrate to S/4HANA, historical data from ECC or earlier versions must be archived securely to ensure compliance and cost efficiency.
• SAP ECC – With ECC maintenance ending, enterprises need to decommission legacy ECC systems while preserving payroll, finance, and HR data for 7–10+ years of retention.
• SAP ILM (Information Lifecycle Management) – Policy-driven retention and legal hold management are critical for SAP environments. Archival ensures SAP ILM policies extend beyond live systems.
• SAP Auxiliary Systems – Secondary or supporting SAP Auxiliary modules (e.g., BW, CRM, SRM) also require archiving to avoid leaving data silos active after migration.
• SAP HCM: With mainstream maintenance ending, many organizations need to decommission legacy SAP HCM while migrating to S/4HANA or SuccessFactors.

Further Read: SAP HCM to SuccessFactors Migration: What About Old HR Data?

Oracle Decommissioning

Oracle’s 2024–2025 end-of-life (EOL) cycle is forcing hard choices. Older databases, engineered hardware, and a long tail of acquired applications are rolling off Premier/Extended Support, which means higher risk, rising costs, and limited paths to modernize especially if you’re not all-in on OCI.

Databases

• 19c – Premier Support ended Apr 30, 2024; patching generally ends 2026 (or 2027 with ULA).
• 21c – Innovation release; no Extended Support, patching ends Apr 2025.
• 23c – Long-term release; supported to 2032. Initially cloud-first, with staggered availability on other platforms.

Engineered systems & storage

• Exadata X7 support ended Jun 2024; X8 reaches end of support Dec 2025.
• Exalytics X6-4, Exalogic X6-2, SuperCluster M8, several ZFS models, and the Big Data Appliance family hit support end between 2024–2025.

Applications

• Oracle Communications (BRM v12, PDC v12, UIM v7.5, OSM v7.4, Calendar/IM servers) – multiple products end Premier/Extended Support 2024–2025
• Essbase 11.12.x – Extended Support ended in Dec 2024
• Oracle Financial Services suites (AML/KYC/CRR/ALM/IFRS, Model Governance, Data Foundations, Profitability, Liquidity Risk) – numerous 8.0/8.1 releases reach end dates through 2025.
• Utilities (CC&B 2.6.x, C2M 2.6.x, MDM 2.2.x, NMS 2.5.x, etc.) – end dates across 2024–2028 (several in 2025).
• Primavera P6/Portfolio/Analytics 20.x – Dec 2025.
• Oracle Commerce 11.3 – Apr 2025.
• Talari / Oracle SD-WAN 9.x – May 2025.

Further Read: Oracle End of Life 2024–2025: Prepare Before It’s Too Late

Mobius

A legacy Mobius application can hold 30 years of historical content across banking, telecom, and manufacturing. It often stores green-bar mainframe reports in formats like AFP, making extraction and reuse difficult.

With no records management policy in place and costly licensing, hosting, and maintenance, Mobius becomes harder to maintain over time.

JBA

JBA data includes both structured ERP tables and unstructured legacy content, often across outdated AS/400 systems with poor documentation. Many enterprises run multiple JBA versions in different languages, complicating compliance and slowing performance.

Epicor

Epicor ERP stores financial data like ledgers, audit logs, and transaction histories, which are critical for compliance and reporting.

JD Edwards

As enterprises transition away from JD Edwards, preserving historical finance, HR, and manufacturing data is vital for audits and regulatory needs.

PeopleSoft

Frequently retired as organizations adopt Workday or Oracle Cloud, PeopleSoft still contains critical payroll and HR history. While decommissioning PeopleSoft it is of at most importance to preserve audit trials, payroll records, and employee data.

Lotus Notes

With decades of stored email communications and custom workflows, Lotus Notes is notoriously complex to archive. Therefore, it is important to decommission Lotus Notes while ensuring smooth, secure archival that serves eDiscovery and compliance needs across industries.

Informatica ILM

Once reliable for archiving and data lifecycle management, legacy Informatica ILM struggles under growing data volumes and cloud-first strategies. Hence you need a more modern alternative with tiered storage, scalable architecture, and lower maintenance costs.

Cerner

Old Cerner environments continue to incur licensing and infrastructure costs, expose PHI to security risks, and complicate HIPAA compliance. Decommissioning ensures data is securely archived, audit-ready, and accessible without the burden of maintaining outdated systems.

Meditech

Legacy Meditech systems are costly to maintain, create compliance risks with decades of PHI, and make data retrieval for audits or patient care cumbersome.

Siebel CRM

Often replaced by Salesforce or Dynamics 365, Siebel still holds critical customer and regulatory records that require compliant archival.

Mainframe Applications (COBOL/DB2/VSAM)

Mainframe systems are still common in finance, insurance, and government. Retiring these systems involves complex data extraction, format transformation, and preservation of business logic.

ADP EV5

ADP EV5 is a legacy payroll and HR platform still in use in some enterprises, but it lacks the scalability and modern compliance features required today. When replaced by newer ADP solutions or alternative HCM platforms, EV5 decommissioning ensures payroll history, tax filings, and employee records remain accessible for audits and legal needs.

Taleo

Taleo, Oracle’s legacy talent acquisition system, is often retired as organizations consolidate HR platforms. Candidate histories, recruiting workflows, and compliance data must be archived properly to ensure continuity for audits and HR reporting.

NHS Electronic Staff Record (ESR)

The NHS ESR system is one of the largest healthcare workforce platforms in the world. Decommissioning older ESR environments, or versions replaced during modernization projects, requires careful handling of staff records, payroll, and compliance data to meet strict healthcare and public sector regulations.

What are the Benefits of Application Decommissioning

1. Cost Reduction and ROI

• Cut software licensing and maintenance fees, hardware costs, data center space, and admin overhead
• Studies show legacy systems consume 60–80% of IT budgets, with individual applications costing $40K–$120K annually
• Systematic decommissioning can deliver:
• 80% reduction in IT costs for retired systems
• 90% reduction in legacy system costs through archiving
• 40% less server management effort

2. Stronger Security Posture

• Legacy apps often lack modern security patches, MFA, and encryption
• Decommissioning reduces attack surfaces and exposure to vulnerabilities
• Eliminates reliance on unsupported software that creates compliance gaps

3. Compliance and Audit Readiness

• Aligns with retention rules under GDPR, HIPAA, SOX, and industry regulations
• Provides defensible audit trails, legal holds, and tamper-proof archival
• Simplifies governance across fragmented systems

4. Operational Efficiency

• Streamlines IT portfolios, reducing maintenance overhead
• Frees up resources for innovation and cloud-first initiatives
• Delivers measurable results:
• 30% improvement in operational efficiency
• 86% faster restore times
• Improves disaster recovery readiness by consolidating data into governed archives.

5. Strategic Agility

• Enables faster M&A consolidation by eliminating redundant apps
• Unlocks modernization by removing “legacy drag” on cloud adoption
• Improves usability — when data lands in a governed, searchable archive instead of a cold store, teams can answer queries without reviving old systems

Common Misconceptions about Application Decommission Clarified

Here are three of the most common myths and the realities behind them:

Misconception 1: “Decommissioning means all data access is lost.”

• Reality: Proper decommissioning doesn’t delete history. It moves data into a compliant archive where it remains searchable and accessible for business users, auditors, and regulators.

Misconception 2: “Decommissioning doesn’t require technical planning.”

• Reality: Decommissioning requires careful planning from data migration and archival strategies to compliance checks and user access validation. Without this, you risk compliance breaches, audit failures, and operational disruption.

Misconception 3: “Sunsetting and retirement are the same.”

• Reality: Sunsetting is the announcement or gradual phase-out stage, while retirement is the actual end of operations. They are related, but not interchangeable.

The Application Decommissioning Process

Decommissioning is a structured process that ensures data is preserved, compliance is met, and operations continue smoothly.

1. Planning & Assessment

• Inventory candidate applications across the portfolio.
• Conduct business and technical analysis (architecture, dependencies, integrations)
• Map stakeholders (IT, business, compliance, legal) and define responsibilities
• Identify regulatory retention requirements (GDPR, HIPAA, SOX)
• Document cost, security, and operational impacts

2. Dependency Mapping

• Identify databases, downstream systems, reports, and workflows relying on the legacy app

• Plan for continuity to prevent disruption during shutdown

3. Data Classification & Retention

• Categorize data by sensitivity, compliance risk, and business value
• Define what must be retained, archived, or safely purged
• Choose the right archival strategy (active, cold, hybrid)

4. Data Extraction & Archiving

• Implement ETL (Extract, Transform, Load) to migrate data
• Preserve business context with semantic data containers
• Apply security controls: encryption, access management, audit trails
• Configure archival platforms to support long-term compliance and easy retrieval

5. Testing & Validation

• User Acceptance Testing (UAT) with representative data sets
• Verify integrity and accessibility of migrated data
• Test performance of archival queries and reporting
• Confirm compliance with retention rules and audit needs
• Run disaster recovery scenarios

6. User Communication & Change Management

• Notify business users about upcoming changes and archival access
• Provide training on how to retrieve data from the new archive

7. System Shutdown

• Execute a controlled, phased shutdown of the application
• Terminate user access with full audit trail capture
• Remove network connections, decommission associated databases and storage
• Securely dispose of hardware containing sensitive data

8. Documentation & Governance

• Document the process, validation steps, and retention policies applied
• Ensure compliance evidence is available for audits
• Establish ongoing retention schedules and access controls

9. Ongoing Retention & Access Management

• Monitor archival system performance and access requests
• Maintain audit logs, legal holds, and policy updates
• Regularly review archival strategies to align with evolving regulations and business needs

Best Tools for Application Decommissioning

Choosing the right tool is critical to ensure smooth shutdown of legacy applications while maintaining compliant access to historical data.

Here are five of the most recognized solutions in the market:

1. Archon Data Store™ (ADS)

Archon Data Store™ (ADS) is designed specifically for application decommissioning and intelligent data archiving. ADS combines cloud-native scalability, compliance-first design, and multi-platform integration to ensure enterprises can retire legacy systems without losing access to critical business data.

It provides a single, governed archive that works across ERP, CRM, HR, and custom applications, making historical data secure, searchable, and ready for audits or analytics.

Key Benefits:

• Cloud-native architecture for scalable, cost-effective data management
• End-to-end compliance support (GDPR, HIPAA, SOX, regional mandates)
• Multi-platform coverage: SAP, JD Edwards, Lotus Notes, Epicor, PeopleSoft, and more
• AI-powered metadata for fast search and retrieval

2. Proceed Group

Proceed is focused on SAP and ILM environments. It includes pre-defined report sets to support business, audit, and legal requirements, and it provides access to legacy data after system shutdown. Organizations using the tool often adopt it to reduce costs associated with keeping redundant SAP systems online.

3. SNP Group – Kyano Datafridge

SNP’s Kyano Datafridge is designed for SAP transformation projects, especially in the context of S/4HANA migrations. It is used in scenarios such as mergers, acquisitions, and system consolidations. The tool provides access to legacy data with audit trails while enabling system retirement.

4. AvenDATA

AvenDATA is used for archiving data from legacy ERP, CRM, and mainframe systems. It includes a retrieval interface that allows users to search across archived data. The company also provides services for handling complex decommissioning projects at scale.

Best Practices for Decommissioning Legacy Systems

Adopt Intelligent Archiving; Not Passive Storage

Decommissioning projects fail when they treat archiving as a simple “lift and dump” exercise. A best-practice approach is to archive all data initially, avoiding long upfront analysis delays and delivering faster cost savings.

Archiving should be metadata-driven so that records remain searchable, reportable, and audit ready. Preserving business context is equally important — relationships, workflows, and logic must be retained so archived data is actually usable rather than locked away.

Build Cross-Functional Teams

Decommissioning succeeds when it is managed as a cross-functional program rather than an IT-only initiative.

Executive sponsors are needed to align budgets and strategy, IT teams handle infrastructure, security, and integrations, and business stakeholders ensure reporting and access requirements are met. Legal and compliance officers define regulatory obligations.

This blend of perspectives helps avoid gaps and ensures that both technical and business needs are addressed.

Implement Phased, Well-Governed Execution

Instead of switching everything off at once, use phased rollouts to minimize disruption and validate progress at each stage. Pilot projects on non-critical systems provide a safe way to test processes before scaling.

Comprehensive documentation of every decision, policy, and technical step creates a defensible audit trail. Security protocols like encryption, access controls, audit logs, and WORM storage should be applied throughout the process to protect data integrity.

Plan for Risk and Resilience

Every decommissioning plan should include contingency measures. Backup and rollback options protect against migration errors, while continuous validation ensures data integrity and access are maintained in the archive.

Disaster recovery testing is another essential safeguard, confirming that archived data can still be retrieved under stress scenarios.

Choose the Right Technology Platform

Not every archiving platform is built for decommissioning. The right technology must be able to scale with future data growth, support compliance obligations across GDPR, HIPAA, SOX, or industry-specific regulations.

It should also integrate with enterprise security frameworks such as Active Directory or IAM. Vendor viability and long-term roadmap should also be considered to ensure ongoing support and stability.

Align with Modernization Strategy

Finally, application decommissioning should be aligned with the broader modernization agenda. In some cases, systems are replaced entirely with modern cloud-native platforms. In others, applications are retired permanently because they no longer provide business value.

A third path is to archive: deactivating systems but retaining data in governed archives. Most enterprises use a combination of these approaches, depending on system criticality and compliance requirements.

Why Archon for Application Decommissioning

Archon Data Store™ (ADS) is built specifically to help enterprises retire legacy applications without losing control of their data. Unlike simple storage or passive archiving, ADS provides a secure, scalable, and compliant platform for decommissioning across diverse applications including SAP, Mobius, JD Edwards, Lotus Notes, Epicor, Informatica ILM, PeopleSoft, and more.

With its cloud-native architecture, ADS ensures organizations can reduce costs while maintaining long-term access to critical records for audits, legal requests, and business continuity. It integrates automated retention policies, metadata-driven search, and a secure data bunker architecture to protect PII and PHI, making archived data both safe and usable.

Key Benefits of ADS

• Compliance-first: Meets global regulations like GDPR, HIPAA, SOX, and DPDPA
• Cost savings: Achieves up to 90% reductions in infrastructure and support costs while eliminating licensing fees for legacy systems
• Security: Protects sensitive data with encryption, masking, RBAC, tokenization, and logical air-gapped segregation
• Accessibility: Enables sub-second eDiscovery, ad-hoc queries, and metadata-driven retrieval for both structured and unstructured content
• Performance & agility: Makes production systems lighter, freeing IT resources for modernization and digital transformation

SAP Decommissioning

SAP is one of the most frequent and urgent decommissioning scenarios because of SAP’s roadmap: mainstream maintenance for SAP ECC is ending, making migration to SAP S/4HANA mandatory. This shift forces enterprises to address decades of data growth across HR, finance, sales, and distribution. Much of it is no longer needed for day-to-day operations, but still critical for audits, compliance, or historical reference.

The challenges are clear:

• Escalating infrastructure and storage costs
• Licensing overheads for data you no longer use
• Slower production system performance as databases bloat
• More complex, expensive S/4HANA migrations weighed down by historical data
• Compliance and legal discovery risks if data is mishandled

Archon Data Store (ADS) addresses these issues directly:

• Unified archival & retention: Retire SAP ECC systems securely while keeping historical records accessible for business, audit, and compliance needs
• S/4HANA optimization: Offload inactive or auxiliary data to improve migration performance and reduce storage cost
• Flexible strategies: Archive both existing S/4HANA data and live transactional data for continuous efficiency
• Auxiliary system management: Offload high-volume SAP BW, CRM, and SRM data into low-cost, regulation-ready archives
• Compliance-first design: Built to handle GDPR, SOX, HIPAA, and industry retention mandates with intelligent metadata tagging and SAP-native integration

Case Study: Medtronic

When Medtronic grew through acquisitions, it inherited hundreds of redundant applications. Many of which are inactive, costly to maintain, and creating unnecessary technology debt. These “zombie systems” consumed millions in licensing, infrastructure, and support, while posing compliance risks if data was lost or mismanaged.

With Archon Suite, Medtronic established an internal application decommissioning team. Together, they built a structured decommissioning program evaluating retention requirements, maintaining data custody, and retiring inactive systems without disrupting compliance.

The result: millions of dollars saved annually, a leaner IT environment, and streamlined operations.

Archon Suite has been trusted by global enterprises facing similar challenges. Whether driven by mergers and acquisitions, cloud migration, or cost optimization, ADS empowers organizations to retire legacy systems while keeping historical data compliant, secure, and accessible for years to come.

👉 Would you like a customized consultation for your application decommissioning strategy? Contact us

Andrew Marsh

A seasoned IT leader with 20+ years of experience across legacy systems and modern enterprise technologies. Specializes in digital transformation, cloud architecture, and enterprise content strategy, with a proven track record of building high-performing teams and long-term customer partnerships.