What happens if I load 320 build limit world in OLD VERSION?! (1.16.220.50)

In this video, I tried to load a minecraft world that has a height limit of 320 blocks and is also utilizing those limit in a minecraft version that only got 256 blocks limit which is pretty much all the minecraft versions below 1.16.220.50. The old minecraft versions did not support 320 blocks so what do you think will happen?
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■■■■■■■■■■■■About this video■■■■■■■■■■■■
App that I use to record: Rec.
OR if I am recording on PC, then I use Windows Key + G to record screen and I use my phone to record sound.
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■■■■■■■■■■Video editing software■■■■■■■■■■
)Main: Adobe Premiere Pro
)Animations: Adobe After Effects
)Thumbnail: Adobe photo shop
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■■■■■■■■■■■■ Music(s) used ■■■■■■■■■■■■■
) Darude Sandstorm
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Twitter:   / elementx47  
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Thank you so much for watching my video, and have a nice day :D