Long term stability

If I want to write a Haskell program and have it compilable without changes 10 years from now, what would I need to do? What would be needed for that to be possible?

I'm guessing I would want some flags like `-XHaskell98` or similar to explicitly tell the compiler what version of the haskell standard to use. Any other flags that would be helpful?

I would obviously want to minimize the number of external dependencies from hackage, since those frequently have breaking changes. Although setting a max version on them in the cabal file *might* be sufficient to solve that, assuming those older versions are still compilable. The larger issue is that boot-packages like `base` frequently have breaking changes and there is no way to use older versions of `base` with newer versions of the compiler. Is there some alternative base library available that is committed to long term stability?