Modernizing legacy RPG applications can help your organization retain reliable IBM i systems while overcoming the RPG developer shortage.
You have business critical, homegrown, custom applications written in the RPG programming language that have reliably supported your business model for years. Now you find there’s a scarcity of RPG programmers and you fear the shortage will only get worse.
You are not alone.
The IBM i platform is used by a disproportionate number of large enterprises for critical business applications. According to respondents to FORTRA’s 2026 IBM i Marketplace Survey, just under half run more than 75% of their core business applications on IBM i even though they have other systems. In 2025, 91% of those companies using the IBM i platform utilize the RPG programming language. Most of those RPG applications are critical and homegrown. RPG remains the number one programming language used by IBM i shops.
If you are putting a strategic plan in place, perhaps you’ve investigated one or more of these alternatives:
- Replatforming and rewriting custom RPG applications in another programming language. Perhaps moving to established languages like C#, PHP or Java in the hope that programmers and associated skillsets will be more readily available.
- Replacing custom RPG applications with a vendor’s software package, eliminating the need for a programmer but introducing the need for expertise in configuring the package and retraining your employees in its use.
- Outsourcing some of your business functions to a third party.
Let’s discuss another alternative, modernizing your existing RPG applications.
In this approach the mindset is “Why throw out the baby with the bathwater?”
Modernizing your RPG applications allows you to keep the platform and custom applications that have reliably supported your business-critical processes for years, while giving you an expanded pool of skilled programmers now and into the future.
Modernization improves RPG program code maintainability without altering the underlying logic or changing its external behavior. It gives you access to a greatly expanded pool of programmers because modernized RPG is very similar to the programming languages familiar to today’s developers. A newly hired developer who has no expertise in RPG can learn this modernized version of RPG easily and quickly.
Most legacy RPG systems have been in place for decades and were written in RPG II, RPG III, or RPG IV – somewhat archaic, fixed format, structured versions of the RPG programming language, often referred to as legacy code. These old versions were originally designed for punched cards, where the meaning of code is determined by its exact position (column) in the line of code rather than by its syntax alone. It’s like filling in a highly structured, rigid form instead of writing an English sentence. The learning curve for those old, fixed format versions of RPG is extremely steep and today’s developers have little incentive to tackle it.
Happily, the RPG programming language has evolved. This newer version of RPG, termed free format RPG or RPG free, is remarkably similar to the modern languages today’s developers are familiar with. This similarity means the learning curve for any of them to learn RPG free is very gentle. The same tools they are familiar with for working with modern program code (VS Code, GitHub, …) are now available for RPG free.
Here’s an example of fixed format RPG as opposed to RPG free——–
English sentence: If X is less than 50, add 1 to a counter.
Fixed format RPG: 3 lines of code
- Put a ‘C’ in column 6
- Put ‘X’ in columns 18-19
- Put ‘IFLT’ in columns 28-31
- Put ‘50’ in columns 33-34
Next line
- Put ‘C’ in column 6
- Put ‘ADD’ in columns 28-30
- Put ‘1’ in column 33
- Put ‘COUNT’ in columns 43-47
Next line
- Put a ‘C’ in column 6
- Put ‘ENDIF in columns 28-32
Here’s that same code written in RPG free:
if X < 50;
count += 1;
endif;
Here’s that same code written in C# (a well-established language widely used for new development):
if (x < 50)
{
count++;
}
Notice how similar the new RPG free is to other modern programming languages?
Converting old, fixed format RPG code to RPG free has become magnitudes easier with the advent of AI tools created specifically for the purpose of converting legacy RPG code to RPG free. Of note is IBM’s launch of Project Bob on March 24, 2026. Project Bob takes old RPG code and transforms it into modern, free-format RPG. As an added bonus, Bob can explain the code. This is extremely valuable since most legacy RPG systems have little or no documentation. If there is documentation, it’s often out of date and inaccurate.
Once your legacy code has been updated to RPG free, you’ve opened the door to a steady supply of programmers who can quickly learn it, understand it, and maintain it. AI coding assistants, available for all modern programming languages, are also available for RPG free. This makes it even easier to source programmers to maintain your business-critical processes written in RPG.
If you like this approach and want to take it beyond the basics of converting your program code from legacy RPG to RPG free, you can modernize even further now or at a later date:
- Green screens can be replaced with web-based GUI’s
- Monolithic code can be modularized and extracted as web services
- Some, or all, of your RPG applications can be migrated to the cloud
At Keller Schroeder we are focused on helping you understand the options available for meeting this challenge and supporting you as you implement your chosen option. Please reach out to your Select Account Manager or any member of our team to get started.
We’re here to help.
