This situation is quite common in practice, especially for production companies. The most important thing is to break the project into modules and integrate modern practices step by step for each module. A good approach for splitting can be based on the module or library related to the programming language; for example, in C++, I would focus on a library or executable for that purpose. Additionally, the order of integration should not be random—you should either start with the lowest-level modules and move up to the highest-level ones, or vice versa.

The approach to handling legacy systems depends on the project’s goal and migration strategy. If the focus is on moving to newer technology, a direct approach is more efficient—migrating modules into a new application with modern practices from the start. However, if the goal is to update the legacy system itself, a gradual approach works best. Migrating modules step by step, introducing unit tests as updates are made, ensures stability. Setting clear goals for each sprint helps balance continuous development with incremental modernization.

Balancing legacy systems with modern practices requires a gradual, thoughtful approach. First, I assess and document the legacy code to fully understand its limitations and areas for improvement. Then, I introduce automated testing to safeguard existing functionality as we make changes. Rather than overhauling everything at once, I refactor small, manageable sections of the legacy code, integrating modern practices step by step. This minimizes disruption while ensuring stability, allowing the system to evolve without compromising on quality or functionality. It’s about combining caution with progress to keep everything aligned.

𝗔𝘀𝘀𝗲𝘀𝘀 𝗟𝗲𝗴𝗮𝗰𝘆 𝗖𝗼𝗱𝗲 Understand the existing code’s structure and limitations before making changes. 𝗣𝗿𝗶𝗼𝗿𝗶𝘁𝗶𝘇𝗲 𝗥𝗲𝗳𝗮𝗰𝘁𝗼𝗿𝗶𝗻𝗴 Gradually update outdated sections to align with modern practices. 𝗠𝗮𝗶𝗻𝘁𝗮𝗶𝗻 𝗖𝗼𝗺𝗽𝗮𝘁𝗶𝗯𝗶𝗹𝗶𝘁𝘆 Ensure new code works smoothly with existing systems. 𝗜𝗻𝗰𝗿𝗲𝗺𝗲𝗻𝘁𝗮𝗹 𝗨𝗽𝗴𝗿𝗮𝗱𝗲𝘀 Introduce improvements step by step to avoid disruption. 𝗗𝗼𝗰𝘂𝗺𝗲𝗻𝘁 𝗖𝗵𝗮𝗻𝗴𝗲𝘀 Keep clear records of updates to help future developers transition smoothly.

First take the time to thoroughly understand the existing codebase, identifying both its strengths and areas for improvement. Gradually implement refactoring while ensuring that core functionality remains intact. Incorporating automated tests can help prevent regressions as you modernize the code. Foster teamwork and knowledge sharing to generate creative solutions, and adopt agile methodologies for flexibility in the integration process. Balancing respect for the legacy system with a commitment to modern practices is key!