AS400 Migration to Cloud: A Complete Guide to Modernize Your Enterprise

There is no doubt the AS400 has served its purpose with strength and reliability. Many businesses still trust it because it has never given them a reason to worry. It runs quietly in the background, it processes transactions, it stores critical data, and it rarely complains. 

That kind of stability is rare. But in today’s environment, stability alone is not enough.

The business world has moved forward. Expectations have changed. Everything now runs on speed, connectivity, and the ability to adapt quickly. Systems are expected to scale within minutes, integrate across platforms effortlessly, and support technologies like AI, real-time analytics, and mobile access. 

The AS400 was not designed for that. It is a closed architecture built for a time when digital meant something very different.

It’s Getting Harder to Keep AS400 Running

Keeping the AS400 running is becoming more expensive with each passing year. Not just in terms of hardware and software, but also in people. Finding professionals who know how to maintain it, or even understand its core programming languages like RPG, is becoming harder. Most IT teams today are trained in cloud-native platforms, not legacy mainframes.

There is also the issue of security. AS400 systems do offer some level of protection, but they do not meet the standards required for modern cybersecurity. Cloud platforms are built with security in every layer. They come with automatic updates, compliance tools, and continuous monitoring. Running a business on AS400 means accepting a higher level of risk, even if everything appears to be working fine on the surface.

Another quiet challenge is integration. The business doesn’t run on a single platform anymore. Sales, marketing, logistics, customer service—they all run on different tools that need to talk to each other. The AS400 was never meant to be part of a cloud-based ecosystem. Making it fit requires extra work, custom code, or third-party solutions that increase complexity and cost.

None of this means the AS400 is broken. It means it was built for a different time. And holding on to it just because it still works can slowly pull the business backward. When competitors are moving faster, building smarter, and making data-driven decisions in real time, staying with an older system comes with a cost that isn’t always visible, but is always real.

Stability Without Scalability Is Not Sustainable

That old AS400 has done its part, no doubt. It ran the business when everything was slower, simpler, and mostly offline. But today, it’s not just old, it’s becoming a liability. Every month it stays in place, the business is exposed to growing risks, and these aren't small issues that can be ignored anymore.

Security is the biggest concern. According to the 2025 IBM i Marketplace Survey, 79% of IBM i users ranked cybersecurity as their top challenge. These machines weren’t built for today’s threat landscape, malware, ransomware, data breaches. Once inside, there's no layered defense.

Then there’s the cost. Maintenance of AS400s doesn’t just drain the IT budget, it locks teams into expensive licensing, outdated support contracts, and hardware that eats power like it’s still the 90s.

And the worst part? Integrative Systems shows that migrating to cloud could cut these costs by up to 40%, all while improving speed and resilience.

What’s even more dangerous is the silence, no alarms ringing when the talent quietly disappears. The people who understand these systems are retiring, and newer professionals aren’t interested in learning RPG or COBOL. The skill gap is growing fast, and most companies are unprepared.

And integration? 

It’s not just clunky. It’s brittle.

Businesses trying to connect AS400 with cloud apps, APIs, and digital workflows find themselves building costly workarounds, every change a new headache. 

Staying on AS400 is not caution. It’s gambling, with time, with data, and with the future of the entire enterprise.

From Legacy to Leadership: A Practical Path to Modernize the Enterprise

There comes a time when holding on too tightly to what worked yesterday begins to cost more than it gives. The AS400 has stood firm for years, but if it's still running the backbone of business today, it's time to think carefully. 

Moving to the cloud isn’t about replacing something old just for the sake of it. It’s about preparing for what lies ahead, so that when the next challenge shows up, the system bends, adapts, and delivers instead of holding things back.

The process starts with clarity. Every piece of application and data running on AS400 needs to be reviewed, not with fear but with focus. 

Some systems can move to the cloud easily without changing a line of code. This is called lift-and-shift, and it works well when speed and budget are a priority. But not every workload behaves the same once it moves.

So before migrating the core parts of the business, testing in a cloud environment helps find what needs to be fixed before it breaks anything important.

Data migration is another challenge that deserves attention. Moving everything across the internet can take a long time, especially with years of business history involved. Using secure physical storage or optimized transfer services helps avoid long delays. 

While all this happens, the data must be protected like a locked vault. Encryption and safe channels matter here because during a move, data is at its most exposed.

And don’t forget the people. Those who’ve worked with AS400 for years will need time to get used to the new systems. That change shouldn’t feel like a threat. It should feel like progress. 

With the right training, even a complex cloud interface can become just another tool that supports good work. The aim isn’t to replace knowledge, but to extend it.

Even after everything moves, it's wise not to shut off the old system too quickly. Let the new setup prove itself. Keep the legacy system running in the background for a while. That safety net allows small mistakes to be fixed without big consequences. And once the new platform proves it can handle everything, faster, safer, and more flexibly, then let the old system rest.

That’s how a business stays strong in the long run. It’s not just about jumping to the latest trend. It’s about building a bridge from what worked to what will work better.

Replacing What Works with What Wins: Why AS400 Migration Pays Off

Upgrading a system isn’t just about switching tools. It’s a decision to stop surviving and start growing. Those who moved from AS400 to the cloud didn’t just replace a machine, they unlocked a different kind of business altogether.

The first thing that changed was the cost. And not just small savings here and there. We're talking about the real impact. After migrating, some companies reduced batch processing time by 70% and saw up to a 1000% improvement in scalability. 

That means when demand spiked, their systems didn’t slow down, they responded instantly.

But it wasn’t only about speed. It was about safety. Modern cloud platforms now come with built-in encryption, compliance, and real-time monitoring, something the old systems were never designed to handle. 

In today’s world, where threats evolve every day, that kind of protection isn’t optional anymore.

Another shift came in the people. With AS400, skilled experts are retiring, and replacements are rare. But once businesses moved to the cloud, they found a wider pool of professionals already trained on new platforms, people who not only knew the tech but brought fresh thinking to the table.

And the biggest benefit? 

New tools became available.

Artificial intelligence, predictive analytics, and process automation, these are no longer just buzzwords. They’re part of how smart businesses make faster decisions, serve customers better, and adapt to change without panic.

Holding on to AS400 might still feel safe. But the world has changed. And those who took the step forward didn’t just modernize—they gave their business the kind of future it could grow into.

When It's Time to Move Forward, Choose a Partner Who Knows the Way

There comes a moment when holding onto the familiar starts to hold you back. The AS400 has been a reliable workhorse, but the demands of today's digital landscape require agility, scalability, and integration that legacy systems struggle to provide. Transitioning to the cloud isn't just about keeping up; it's about positioning your business to lead.

Entrans understands this journey. With a proven track record in modernizing legacy systems, they specialize in seamless AS400 to cloud migrations. Their approach isn't one-size-fits-all; it's tailored to your unique business needs, ensuring minimal disruption and maximum efficiency.

By partnering with Entrans, you gain access to:

• Expertise in Legacy Systems: Deep knowledge of AS400 intricacies ensures a smooth transition.
  
• Customized Migration Strategies: Whether it's rehosting, replatforming, or refactoring, they choose the path that best suits your objectives.
  
• Advanced Security Protocols: Protecting your data during and after migration is paramount.
  
• Post-Migration Support: Ensuring your new environment operates optimally with ongoing assistance.
  

Making the move is a significant decision, but with the right partner, it's a step toward a more agile and resilient future.

Connect with Entrans for a free consultation to explore how your systems can evolve, without disrupting what works.