Your Dynamics NAV upgrade path, mapped out clearly.
This is the same guide we walk clients through in a discovery call: why the timeline matters, the two ways to get to Business Central, what actually happens to your data during migration, and the process we run from assessment to go-live.
Dynamics NAV's support clock, version by version
Microsoft supports Dynamics NAV under its Fixed Lifecycle Policy: five years of mainstream support (features, fixes, and full technical support), followed by five years of extended support (security patches and critical fixes only, no new features). Every NAV version has already exited mainstream support. Here's where each remaining version stands on extended support.
What "out of support" actually means
Once extended support ends, Microsoft stops issuing security patches, regulatory updates, and critical bug fixes for that version — permanently. An unpatched ERP system sitting at the center of your financial data, banking connections, and payroll becomes a compliance and security exposure that only grows over time. There is no successor support tier within the NAV product line; Business Central is the only supported forward path.
Technical upgrade vs. reimplementation
There isn't a single "upgrade path" — there are two, and the right one depends on how customized your current NAV environment is and whether you want to keep your existing processes or use the move as a chance to redesign them.
Technical upgrade
- Migrates your existing data, chart of accounts, and configuration directly into Business Central
- Fastest option — a straightforward technical upgrade can take as little as 2–4 weeks; most run 2–4 months depending on customization
- Minimizes disruption and preserves what already works
- Best suited to environments with light customization and NAV 2016–2018 as a starting point
- Custom code still needs to be converted into the modern extension model — this is usually the biggest variable in timeline and cost
Reimplementation
- Rebuilds your ERP in Business Central around how the business runs today, not how it ran when NAV was first configured
- Typically takes 3–6 months depending on scope and company size
- Master records, opening balances, and open transactions migrate in; full history is usually archived separately for reference
- Best suited to heavily customized environments, older NAV versions, or businesses that have outgrown their original configuration
- Removes accumulated technical debt and legacy workarounds instead of carrying them forward
| Factor | Technical upgrade | Reimplementation |
|---|---|---|
| Typical timeline | 2–4 months | 3–6 months |
| Historical data | Migrated in full | Core data in; full history archived |
| Customizations | Converted to extensions | Rebuilt only where still needed |
| Process redesign | Minimal | Significant opportunity |
| Best for | Lightly customized, recent NAV versions | Heavily customized or older environments |
How the technical migration actually works
Moving from an on-premises database to Business Central online isn't an export/import job or an API integration — it's a structured, database-level process. Here's what's actually happening during a cloud migration.
Database-to-database replication, not an API sync
Microsoft's cloud migration tool connects directly to your source SQL Server database and replicates company data table by table into Business Central's Azure SQL environment — it doesn't run your old application logic or move data through the API layer.
Platform prerequisites
Your on-premises SQL Server needs to be on SQL Server 2016 or later, with the database at compatibility level 130 or higher, before migration can begin. Older environments typically need a database upgrade step first.
The cloud environment stays read-only until cutover
While replication is running, the online environment is set up with read-only access (using Microsoft's Intelligent Cloud permission set) so users can preview data without creating conflicts. The on-premises system remains the system of record until you explicitly go live.
Extensions and custom tables must match the SaaS schema
This is where most migrations run into friction. Custom fields, tables, and ISV add-ons need to be rebuilt as extensions that match Business Central online's schema — anything that doesn't match will fail to replicate, sometimes silently.
Deciding how much history to bring forward
Every additional year of transactional history slows replication and increases the chance of reconciliation issues. Most organizations bring forward two to three years of active history and archive the rest for audit and reporting purposes.
Go-live and decommission
Once data is validated, users cut over to the online environment, the on-premises deployment is decommissioned, and the business gains access to Business Central's cloud-only capabilities — including AI-powered Copilot features, which are available only to online customers.
The Exonex NAV-to-Business-Central process
System & data assessment
We inventory your NAV version, customizations, ISV add-ons, and data volume, and confirm whether you're on a supported upgrade path.
Choose the path
We recommend technical upgrade or reimplementation based on customization level, business goals, and budget — with the trade-offs laid out plainly.
Build & migrate
Extensions are rebuilt or converted, data is cleaned and scoped, and migration runs against a sandbox environment first.
Test, train, cut over
User acceptance testing, role-based training, and a planned cutover — followed by hypercare support in the weeks after go-live.
NAV upgrade FAQ
What happens to our existing customizations?
They need to be converted into Business Central's modern extension model — the old C/SIDE-style modifications aren't compatible with Business Central online. In many cases, functionality that used to require a custom modification is now available out of the box, which reduces the amount that needs rebuilding.
Can we keep all our historical data?
Yes, but we'd generally advise against bringing everything forward automatically. Most clients migrate 2–3 years of active transactional history into Business Central and keep older records archived and accessible for audit or reporting purposes, which keeps the new system fast and clean.
Do we need new hardware or infrastructure?
No — that's one of the main benefits of moving to Business Central online. It's a fully managed SaaS product, so there's no server, database, or infrastructure for your team to maintain going forward.
What if our ISV add-ons aren't available for Business Central?
We check this early in the assessment phase. Many ISV vendors have Business Central-compatible versions of their add-ons; where one isn't available, we scope a replacement using standard functionality or a custom extension.
How long will the whole project take?
A straightforward technical upgrade can take as little as a few weeks for a small, lightly customized environment, though most run 2–4 months. A full reimplementation typically takes 3–6 months. We'll give you a firm estimate after the assessment phase, not before.
Will we lose access to the system during migration?
No. Your on-premises NAV system stays fully operational as the system of record throughout the migration process. You only cut over to Business Central once data has been validated and your team is trained.
Not sure where your NAV version stands?
Send us your NAV version and we'll tell you honestly how much runway you have and what the upgrade would involve.