Dynamics AX and Dynamics 365 are both Microsoft ERP platforms, but they are fundamentally different products. Dynamics AX is an on-premise system that Microsoft stopped actively developing years ago, while Dynamics 365 Finance and Supply Chain Management is a cloud-based platform built on a modern architecture. If you are running Dynamics AX today, you are essentially running legacy software — and at some point, a migration decision becomes unavoidable.
Below, we answer the most common questions organisations ask when they start comparing the two platforms and thinking about what comes next.
Is Dynamics AX still supported by Microsoft?
Dynamics AX has reached the end of mainstream support for all major versions. Microsoft ended mainstream support for Dynamics AX 2012 R3 in 2018, and extended support concluded in 2023. This means Microsoft no longer releases new features, non-security fixes, or design changes for the product. Security updates under extended support may still apply depending on your version, but the platform is effectively frozen.
Running a system without active vendor support creates real risk. You rely on your internal team or third-party partners to maintain stability, and you lose access to the continuous improvements that modern ERP platforms deliver. As of 2026, any organisation still on Dynamics AX is working against the clock. The longer the migration is delayed, the wider the capability gap becomes and the harder the eventual transition gets.
What are the main technical differences between Dynamics AX and Dynamics 365?
The core difference between Dynamics AX and Dynamics 365 is the architecture. Dynamics AX is an on-premise application installed on your own servers. Dynamics 365 Finance and Supply Chain Management is a cloud-native platform hosted on Microsoft Azure, updated continuously, and accessed through a browser. This is not just a hosting change — it fundamentally affects how the system is maintained, extended, and integrated.
Here are the most important technical distinctions:
- Deployment model: AX runs on local infrastructure; Dynamics 365 runs in the cloud with no server management required on your side
- Update cadence: AX updates were infrequent and manual; Dynamics 365 receives continuous, automatic updates from Microsoft
- Customisation approach: AX relied heavily on code-level customisations that made upgrades painful; Dynamics 365 uses extensions and a low-code approach that is easier to maintain
- Integration capabilities: Dynamics 365 connects natively with the Microsoft Power Platform, Azure services, and a wide ecosystem of third-party tools
- User experience: Dynamics 365 has a modern, responsive interface designed for both desktop and mobile use
- Licensing: AX used a perpetual licence model; Dynamics 365 uses a subscription model per user per month
These differences mean that moving from AX to Dynamics 365 is not an upgrade in the traditional sense. It is a full reimplementation that requires careful planning across processes, data, and people.
What does migrating from Dynamics AX to Dynamics 365 actually involve?
Migrating from Dynamics AX to Dynamics 365 involves a full ERP reimplementation rather than a simple technical lift-and-shift. Your existing customisations, integrations, and data structures do not transfer automatically. Each element needs to be assessed, redesigned where necessary, and rebuilt within the new platform’s architecture.
A well-structured migration typically covers these workstreams:
- Current state analysis: Documenting your existing AX configuration, customisations, and business processes (the As-Is state)
- Future state design: Defining how those processes will work in Dynamics 365 (the To-Be state), often with process improvements built in
- Data migration: Extracting, cleansing, mapping, and loading your data from AX into the new system — this is one of the highest-risk phases of any migration
- Integration redesign: Rebuilding connections to third-party systems using Dynamics 365’s native integration tools
- Testing: Running unit tests, integration tests, and user acceptance testing to confirm the system works correctly before go-live
- Cutover: The final switch from AX to Dynamics 365, which requires precise planning to avoid disruption to operations
- Change management: Preparing your people for the new system, driving adoption, and supporting them through the transition
Data migration deserves particular attention. Years of accumulated data in AX rarely transfers cleanly. Duplicate records, outdated master data, and inconsistent formats all need to be resolved before go-live. Rigorous As-Is/To-Be analysis and structured testing procedures are what prevent data loss and errors from surfacing after the system is live — this is an area where data migration management expertise makes a measurable difference.
How long does an AX to Dynamics 365 migration typically take?
An AX to Dynamics 365 migration typically takes between 12 and 24 months for a mid-to-large enterprise. Smaller organisations with simpler processes and limited customisations may complete the project in 9 to 12 months. Highly complex environments with extensive integrations, multiple legal entities, or significant data quality challenges can run longer.
Several factors influence the timeline:
- The number and complexity of customisations in your current AX system
- The volume and quality of data that needs to be migrated
- The number of business units, countries, or legal entities in scope
- The availability and engagement of internal business stakeholders
- The experience of your implementation partner with comparable migrations
One factor that consistently shortens timelines is starting with a clear baseline. Organisations that know exactly where they stand before committing to a roadmap make faster, better decisions throughout the programme. A maturity assessment at the outset gives you that clarity — it identifies gaps in processes, people, and systems before budgets are locked in, which reduces surprises later.
Should you upgrade to Dynamics 365 or switch to a different ERP?
For most organisations already running Dynamics AX, migrating to Dynamics 365 Finance and Supply Chain Management is the most logical path forward. You stay within a familiar Microsoft ecosystem, your team has existing platform knowledge, and the integration with other Microsoft tools is strong. Switching to a completely different ERP means starting from scratch on vendor selection, implementation methodology, and user training.
That said, a platform switch can make sense in specific situations:
- Your business has changed significantly since AX was implemented, and Dynamics 365 no longer fits your industry or operating model
- A merger or acquisition means aligning with a parent company’s existing ERP platform
- Your organisation has specific requirements that another platform, such as SAP S/4HANA, addresses better
The honest answer is that this decision should be based on a structured evaluation of your current processes, future business requirements, and total cost of ownership — not on assumptions. Committing to a multi-year ERP programme without that baseline analysis is one of the most common reasons transformations run over budget or miss their business case. You can explore our full range of services to understand how a structured approach covers every stage of this decision and delivery process.
How Optinus helps with Dynamics AX to Dynamics 365 migrations
We work with organisations across the full AX to Dynamics 365 migration journey — from the first assessment through to post-go-live support. Here is what that looks like in practice:
- Maturity assessment: We start by giving you a clear picture of where your organisation actually stands — processes, data, and people — before any roadmap or budget is committed
- Project and program management: Our consultants have hands-on experience from real ERP migrations at leading multinationals, not just theoretical frameworks
- Data migration management: We use rigorous As-Is/To-Be analysis and structured testing to protect data integrity throughout the migration
- Cutover management: We plan and manage the go-live transition end-to-end, including hypercare and aftercare, so your operations stay uninterrupted
- Change management: We address both the technical and human side of the transition, driving genuine user adoption rather than just delivering training
- Flexible delivery: We work on-site and remotely, across the Netherlands, Belgium, and internationally
If you are evaluating your options for a Dynamics AX migration and want a clear, honest starting point, get in touch with our team or learn more about what we do.
