Dealing with 5 year old code is okay now. In 10 years it will cause you pain. It's like going back to an ex after you lose attraction. It never works out and hurts both parties (in this case your users, because you won't maintain it or want to pretty soon)
And or if you got any dependencies (even to "open" 'stuff') when vulnerabilities and bugs arise that will break the backwards compatibility to your codebase you will definitely be tempted/lured/asked to spend "only 5 mins" to update it.
Just don't. Keep a copy wherever others suggested, keep a photo in the folder with the ex-bf/gf think about it every few years (I wonder how she is doing - in a Morty voice) and quickly move on!
lol. To be clear I like her the way she is... It did not work financially but I believe it is a neat piece of code. I keep "using it" myself regularly ;)
Dealing with 5 year old code is okay now. In 10 years it will cause you pain. It's like going back to an ex after you lose attraction. It never works out and hurts both parties (in this case your users, because you won't maintain it or want to pretty soon)