Opposite of "retrofit"

Solution 1:

I suspect that there may be no correct answer. I looked up this question, and it gave me pro- and antero- as antonyms. Profit. No. Anterofit. Doesn't even exist.

There may not be an antonym for this word. However, there's a myriad of other words that mean what you want, such as:

• Update
• Refit
• Modernize
• Renovate

Solution 2:

I would normally just use adapt.

Of course, that's a hypernym of retrofit, but there's a good reason why we have a specific term for using something new in an older context; the challenges are different, because we can't plan for how to design the old context to work with the new component because the old context is by definition not what we are designing. Conversely, if we are using an existing component in a newer context (and indeed, we will be doing so almost every time; we'll always have some elements that pre-exist) we have the ability to plan the wider context to match well, which while still posing challenges, is generally more easily done.

This would cover physical items (adapting an engine component to work in a new engine), digital items (adapting a general purpose software library to better serve a specific use) or intellectual property (adapting an existing character or location, whether fictional or based on reality, to serve a game or narrative).