The main issue that organisations running older, legacy applications are facing today, is generally a skills shortage. Sure enough, the applications themselves have no real issues. But there are simply not enough skilled people around anymore to support them properly. Eventually those organisations arrive at the decision that some sort of modernisation process is in order. But how do you go about such an important challenge?

There definitely is no shortage of options, when it comes to modernising legacy applications. From simply rehosting your applications to completely rebuilding or even replacing them, a whole range of different modernisation strategies is at your disposal. All have different purposes, effects, values, costs, risks and impacts. But which is the right one for you?

Replacement isn’t your only option

As Stefan van der Zijden, research director at Gartner, very neatly puts it: “Application modernization is not one ‘thing’. Replacement isn’t the only option.” He proceeds to explain: “If you’re faced with a legacy challenge, the best approach depends on the problem you’re trying to solve. The key is to understand if your problem is caused by the technology, the architecture or the functionality of your application, and how each modernisation approach improves those aspects.”

In addition to the problem(s) you want to solve, adopting a suitable modernisation strategy also takes on board the expected profit(s) and any current issue(s). Gartner has identified seven common strategies that highlight these issues.

Rearchitecting strategy

After conducting a thorough assessment, the best choice for any organization facing the profound skills shortage problem mentioned above, is between rearchitect and rebuild or replace.

When you rearchitect an application, you materially alter its code and isolate its functional bricks in order to reintegrate them into a new, flexible and scalable structure. That way you can shift your application to a new application architecture and fully exploit new and better capabilities of your application platform. Rearchitecting has a moderate cost and risk, but will yield only moderate results.

Rebuild/replace strategies

Rebuilding or replacing provides the best results, but at a higher cost and risk. When you rebuild an application, you completely rewrite or redesign it from scratch while preserving its scope and specifications. When you replace it, you eliminate the former application altogether and put another in its place, taking new requirements and needs into account.

Replacement as a strategy is particularly interesting when the modernisation project involves a much higher investment than the expected benefits. In that case, Gartner suggests reconsidering your limitations and goals in order to determine if there isn’t already an application on the market that can meet your needs. Replacing your legacy application with a SaaS solution, for instance, will release you from design and development work, freeing up time and resources for your most important applications. Be wary of the integration process, however, for that too can be laborious, time-consuming and therefore costly.

Continuous modernisation

Gartner predicts that every dollar you invest in digital business innovation through to the end of 2020 will require you to spend at least three times that amount to continuously modernize your legacy application portfolio. To spend that money effectively, you will need to carefully select one of the seven different modernisation approaches.

To find out more about Gartner’s modernisation strategies, particularly with and for the Cloud, please check this blog post by my colleague Benjamin Chossat, CTO Telecom Media Entertainment.