Plenty of finance teams have lived in Dynamics GP for years. It’s familiar, stable, and deeply customized. For a long time, that was the point.
Now there’s a clock on the relationship. Microsoft has announced Dynamics GP product support and updates end December 31, 2029, and security updates, if needed, run until April 30, 2031.
That timeline creates urgency, but it also creates a rare opportunity. Migrations tend to confirm what most teams already feel: the hardest part isn’t the ERP. It’s the layer of customizations and workarounds built around it, especially in AP.
Here’s the hidden decision inside every migration plan: Will you recreate the same AP workarounds in a new system, or use the move to simplify and strengthen controls?
Customizations are not automatically bad. Many were built for good reasons: a missing report, a unique approval path, a special vendor requirement, or a department that needed faster turnaround.
The risk builds over time:
Teams discover that what looks like critical customization often includes workarounds that can be replaced, simplified, or retired.
And the longer the customization stack grows, the more it costs to change anything. McKinsey reports CIOs estimate tech debt equals 20% to 40% of the value of their technology estate. That’s why ERP projects get expensive fast, even when the new system is “better.”
During a migration, that drag turns into delays, rework, and the dreaded “we rebuilt it because no one could explain it.”
AP is where real-world variability lives. Invoices arrive in every format. Exceptions are common. Approvals happen between meetings. Vendors change banking details. Departments code things differently.
AP teams often solve friction with:
Those fixes feel practical in the moment. Over time, they create long-term risk: slower close, weaker audit trails, inconsistent controls, and higher fraud exposure.
ERP transitions create noise. New processes. New roles. New access. New approval paths. That’s the perfect environment for mistakes and social engineering.
Verizon’s 2024 Data Breach Investigations Report found the “human element” was a component in 68% of breaches.
Payment fraud isn’t a fringe issue either. AFP’s 2025 Payments Fraud and Control Survey reports 79% of organizations experienced attempted or actual payments fraud activity in 2024, and 63% cite Business Email Compromise (BEC) as the top avenue for fraud attempts. BEC attacks surged 1,760% year-over-year from 2022 to 2023, as threat actors leveraged AI to craft increasingly sophisticated social engineering attacks.
BEC is especially relevant during system changes because it often targets exactly what migrations disrupt: vendor onboarding, vendor banking updates, and payment routing.
That should make every finance leader pause during an ERP transition.
The most expensive migration mistake is simple: rebuilding old workarounds because “that’s how we do it.”
A better approach starts with the result you’re trying to protect. Instead of asking, “How do we rebuild this customization?” ask, “What was this customization trying to accomplish?”
Common AP outcomes worth keeping:
When the outcome is clear, the design choices get easier. A lot of “must-have” customizations turn out to be “we never had time to fix the process.”
Here’s a practical framework that teams can use without turning this into a six-month discovery project.
1) Inventory the reality, not just the code
Include:
For each item, capture:
That last bullet is the key. It separates real controls from habits.
2) Sort everything into four buckets
Keep this simple and decisive:
Most teams find “retire” is bigger than expected. That’s where your migration ROI lives.
3) Decide where work should live
Every modern ERP supports configuration and workflow, but not every workflow belongs inside the ERP.
Invoice intake and approvals don’t have to live inside the ERP just because the ERP exists. High-volume document capture, approvals, and exception handling often work better when they’re standardized outside the ERP so the core system stays clean and scalable. This also helps prevent “custom code creep” from coming back a year after go-live.
4) Make change management part of the build
ERP migrations fail quietly. The system goes live, but adoption drifts. Workarounds return. Controls weaken.
Research shows projects with effective change management met or exceeded objectives 93% of the time, compared to 15% for projects with poor change management. That difference is why process ownership matters as much as system configuration.
Practical steps:
A clean AP workflow after GP isn’t about fancy features. It’s about consistency, visibility, and defensibility.
Strong vendor change controls
Vendor onboarding and banking changes deserve a controlled workflow that captures documentation, verifies requests, and leaves a clear audit trail. This reduces the room that BEC scams exploit, especially during periods of change.
Lower exception volume, faster exception resolution
Exceptions are normal. Chaos is optional.
A modern approach reduces exceptions upstream through better capture and coding standards, then routes remaining exceptions with clear owners and SLAs. That stops AP from becoming a constant follow-up function.
Approvals that move quickly and stand up to scrutiny
Approvals should be fast and trackable. A good workflow answers basic questions instantly:
Once you’ve defined those controls, the ERP choice becomes less scary because you’re not asking it to solve everything.
Many GP customers are moving to NetSuite. Others are choosing Business Central, Dynamics 365 Finance, Sage, or another modern ERP. Plenty are still in evaluation mode.
The destination matters, but the biggest migration risk stays the same across all of them: rebuilding old customizations and AP workarounds without revalidating the outcome. That’s how teams end up with a “new” ERP and the same approval bottlenecks, exception chaos, and control gaps they hoped to leave behind.
So, treat this as an ERP-agnostic principle: configure where you can, customize only when you must, and design AP controls so they’re consistent and defensible regardless of platform.
The key is keeping the outcomes and retiring the workarounds, no matter which ERP you choose next.
Don’t let AP become the catch-all where exceptions, vendor changes, and approvals go to disappear.
Before you finalize your target-state design, pressure test it with a few practical questions:
If you can answer those confidently, you’re far less likely to rebuild GP-era workarounds in your next ERP.
Dynamics GP sunsetting puts a real timeline on your ERP decision, but the bigger risk is what you carry forward. The fastest way to waste a migration is rebuilding years of AP workarounds without questioning what they were actually protecting. Use this moment to keep the outcomes that matter and retire the customizations that quietly added cost, complexity, and exposure.
A strong “post-GP” AP process is simple to explain and hard to break. Vendor changes run through clear controls. Exceptions get routed to the right owner fast. Approvals move quickly, and the audit trail is there when you need it.
If you want to protect the AP side of your migration, onPhase can act as the layer of consistency across the transition, so controls don’t depend on tribal knowledge or last-minute workarounds. We help teams design and standardize invoice intake, approvals, exception handling, and vendor change workflows before go-live, so the new ERP launches cleaner and stays easier to maintain. That’s migration insurance against the most common failure mode: workarounds creeping back in when things get busy.
Before you assume your next ERP will solve AP on its own, this is a helpful follow-up: Why Your ERP Isn’t Solving Your Accounts Payable Problems.