The 7 strategies for legacy moderation: Which fits...

> Key Takeaway: The seven strategies for legacy modernization — Retain, Retire, Rehost, Replatform, Refactor, Rearchitect, and Rebuild — offer different levels of effort and modernization depth. The choice depends on system criticality, technical debt, and strategic business goals.

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*# The 7 strategies for [legacy](/services/legacy modernization)[modernization](/services/legacy modernization): Which fits your company? *

Opened at: 21. January 2026 ## 1. Introduction: The right way for your IT transformation

The decision to touch a legacy system that has grown over years has fallen. But how best to do it? A one-sizefits-all approach does not exist when modernising old systems. The IT analysis house Gartner has defined seven basic strategies that companies can serve as orientation [1].

These range from minimally invasive interventions to complete new development.

Choosing the right strategy is crucial for the success of your modernization project. It not only affects the costs and time required, but also the degree of flexibility, scalability and sustainability achieved.

In this article we will introduce you to the seven strategies in detail and give you a decision-making aid to find the optimal way for your company.

2. Migration options: The fast way to the cloud

Short: Migration options aim to convert existing applications into a new, more modern environment – usually the cloud – with as few changes as possible.

Migration options aim to convert existing applications into a new, more modern environment – usually the cloud – with as few changes as possible. The focus is on fast successes and cost savings in operation.

Strategy 1: Encapsulate (capsules)

In capsules, the legacy system is quasi packed into a "container" and made accessible via modern interfaces (APIs).

The core application itself remains intact.

This approach enables the functionality of the old system to be used quickly for new digital services or mobile applications without having to make profound changes.

• Advantages: Low risk, fast implementation, low cost.

**The core problems of the old system (bad wartability, outdated technology) remain.

Appropriate for: Companies that need to quickly create new digital offers and whose old system is still stable.

Strategy 2: Rehost (Lift & Shift)

Rehosting, also as "Lift & Shift" is the easiest way to the cloud. The application is migrated 1:1 from its own on-premise infrastructure to an infrastructure as a service (IaaS) platform in the cloud. No changes are made to the code itself.

• Advantages: Very fast migration, immediate savings in hardware and operating costs.

• **Does not exploit the potentials of the cloud (e.g. scalability, PaaS services). The application is not "cloud-native".

• Appropriate for: Companies who want to quickly withdraw from their own data center and whose applications do not require cloud-specific adjustments.

Strategy 3: Replatform

This strategy goes one step further than pure rehosting. The application is also migrated into the cloud, but crumbled

References and further reading

Short: The following independent references complement the topics in this article:

The following independent references complement the topics in this article:

• Bitkom – German digital industry association
• German Federal Office for Information Security (BSI)
• European Commission – Digital strategy
• MDN Web Docs (Mozilla)
• W3C – World Wide Web Consortium

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