Code to convert 1.16 to the upcoming 1.17?

[michaelws65]

Since this application is able to read the junk files, would it be possible to create a code to modify the chunk files? A lot of people are worried that their 1.16 worlds will not be able to be converted to 1.17 due to the increase and maximum build height and the decrease below bedrock. If we had a code that could remove the bedrock and add stone blocks below level five and add air blocks above 255 then we could import these chunks into a new 1.17 world? It wouldn't have to be at perfect conversion but at least it would let people continue to play on their worlds with the new updates.