Few things you should know before going in:

Legacy products need a different approach than most modern tech stack applications

The automation framework has to deal with the various legacy platforms used

This means compatibility with those languages, platforms is essential

In some cases it can be advantageous too, e.g. front ends built with some JQuery or custom components might make things easier

The backend might not be as ‘automation friendly’ since it was never designed for anyone other than the developer to understand

Processes, tools and the team, all would come into play

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