Legacy Systems: Common Problems and Tackling Strategies

With the widespread of COVID-19, many IT professionals have come to realize weaknesses in their digital strategies. Many of them happen because they are still …


With the widespread of COVID-19, many IT professionals have come to realize weaknesses in their digital strategies. Many of them happen because they are still residing their data on legacy systems. 

A legacy system is a software and infrastructure that is built on outdated technology. This type of system can cause errors but many organizations are still relying on them. The common reason is the legacy system has become so deeply integrated into the procedures and structure of the organization that it’s too complicated to upgrade to newer technology. Other reasons are it’s too expensive, newer technologies are unfamiliar, or the organization doesn’t have the expertise to dig into this matter.

However, as companies are increasingly adopting technology in their business and operational activities to stay competitive, those obstacles shouldn’t scare you from thinking of adopting the latest technologies. In this article, we’ll share with you common problems with legacy systems that you should be wary of so that you can determine if digital transformation is worthwhile for your business. 

Common Problems with Legacy Systems

Common Problems with Legacy Systems


Cybercrime has been on the rise in recent years. Hackers are becoming more and more sophisticated in their approaches to stealing businesses’ data for financial gain, and while there’s no magic solution to preventing cyber crimes, your business is more likely to experience them under certain circumstances.

Using legacy systems is one of those circumstances. Outdated software and infrastructure are more susceptible to cyber-attacks because hackers have figured out how to bypass old technologies. Outdated software is also neglected by its developers who tend to prioritize their latest models when releasing updates and upgrades. Updates and upgrades come with protection against new malware, so using new technologies will help secure your data. When you rely on old, outdated technology, however, you won’t receive these updates, thus putting your business at risk.

Expensive Maintenance

Organizations tend to assume that upgrading software will cost them an arm and a leg. This can be a bit costly, but from a long-term perspective, upgrading to new technology is often far less expensive than the maintenance of outdated software and the inefficiency it causes. On top of this, you can keep spending money on your legacy system, but it will never reach the level of quality and efficiency of newer models, which means you’re wasting your funding on technology that’ll never catch up with the standards of the contemporary business world.  


One of the most common words that staff use to describe the legacy system of their company is “Slow”. This is the typical characteristic of legacy systems. Long load times, lags, and malfunctions are what employees often experience with legacy systems, and because manufacturers no longer release updates for these issues, there’s no effective way to address them. This inefficiency frustrates users and impairs their productivity. 

Common Issues with Legacy Systems


If you want to integrate newer technologies with your legacy systems, it’s worth noting that a host of problems might occur, because newer software and older ones don’t often integrate well with one another because of their different underlying technology. If you need to stick with a legacy system, do so without trying to bring more advanced models on board, and if you want to upgrade your system, then consider refactoring or retiring your legacy system.

Data Silos

This is an issue that results from incompatibilities. Outdated systems don’t often integrate properly with one another because that’s not something old technology allows for. This means data generated in each system is isolated, which creates data silos. This is a huge problem for big organizations with different types of data, because employees have to go to different tools to find what they need, and it’s very difficult to gather data from different systems in a single place. This is a big time waster and truly frustrating for staff. 

Modern systems such as ERPs don’t have this problem because they offer functionality for all operations of an organization as a single package, and data generated is stored in a single place. 

Lack of Support

Legacy systems often are no longer supported by the manufacturer for technical issues because their sale has come to a halt. This means if you encounter any problem or have any questions while using the system, it’s unlikely that you can get help for troubleshooting from the vendor. Third-party service providers might offer support at a cost, but as a certain technology ages and becomes outdated, technical support for it tends to disappear. 


Many governments have come to enforce new regulations on data protection, such as the GDPR, in their countries, and businesses need to follow these laws if they’re going to operate in these territories. This leads many businesses to need for upgrading their legacy system because their old technology doesn’t suffice to technically obey these new regulations. If your home country enacts such a law, or you want to expand your business to a territory with such a law, legacy systems will become your roadblock.

How To Deal With Legacy Systems

How To Deal With Legacy Systems

Replacing the legacy system with a new one

This strategy is building a new system from scratch. It’s more expensive than the other approaches addressed next and used only when there’s nothing or almost nothing to retain in the old system.

You should replace your legacy system with a new more advanced one if an IT audit reveals things like your current system are built on ancient code that is filled with errors, or the security and performance are problematic, or the current service architecture no longer fulfills your needs. In these circumstances, it doesn’t make technical sense to fix the existing code piece by piece, because doing so will take a lot more time and be much more expensive than just building a new system from scratch. 

It’s worth noting that a thorough replacement of your entire legacy system won’t just improve your performance and security, but is also an opportunity to reassess your current processes and improve them or rearrange them in a way that is more efficient for the future.

Code Refactoring

Refactoring a legacy system is the practice of changing the internal code without interfering with its external behavior. For example, if you have a code snippet that is responsible for a certain calculation, when it’s refactored, the code of the snippet is rewritten in a better cleaner way, but this snippet still serves the same calculation function. Refactoring does not require you to demolish your entire legacy system, which means you just need to spend your money on what needs refactoring while the rest of the system stays the same. 

As you refactor your system, new better code will gradually replace the archaic code, which gives you better performance and security. The implementation won’t disrupt your operation so it’s a very effective and popular method for legacy system modernization. One thing about refactoring is as the refactoring code tackles your old code function by function, the implementation can take many months and is continuous daily progress, but eventually, it will leave the coder better than you found it. 

Code Rewriting

Rewrite is similar to refactoring in a way that it happens at the code level of your system, but the difference is, in a refactor, developers, make micro-changes to clean up the existing code while with a rewrite, they throw almost everything away, and rewrite the function afresh. 

Code rewrite often makes sense for individual functions or when the legacy system is really small. If you have a large system, rewriting it will disrupt your entire business as your system is in production. To successfully rewrite a legacy system, you need to form two teams: one that maintains the old system and another that builds the new one. This means doubling your resources. Businesses often choose code rewrite when there’re small buggy features that they need to replace to improve the performance of the rest of the system. 

Final Words

Dealing with legacy systems is a common and often frustrating reality when you want to employ technology for your business. We hope this article has provided you with valuable information about the problems that are associated with legacy systems and the strategies you can use to begin working on your own.

If your company doesn’t have the expertise to deal with your legacy system in-house, it’s best to find a service provider to help you. 

CMC Global is among the top three IT outsourcing services providers in Vietnam. We operate a large certified team of developers, providing a wide variety of stacks, to help you modernize your legacy system in the most cost-effective way and in the least amount of time. 

For further information, fill out the form below, and our technical team will get in touch shortly to advise!