You certainly can upgrade a world to newer versions, starting at least as far back as InfDev; the game will automatically make the necessary data conversions when upgrading, though it won't maintain continuity with previously generated chunks (this is why the same seed generates a different world in Alpha and 1.16) and in chunks created prior to 1.2, biomes (vegetation color and precipitation) will change since they weren't saved until then. There will also be a few oddities, such as leaves changing to different types as new leaves are added, due to changes in how the game stored their states (you can use this to your advantage as you can get new tree types without having to explore new chunks), and sea level was changed from 64 to 63 in Beta 1.8 so you'll get a 1 block drop off into new chunks (of course, you'll see much bigger cliffs due to changes to terrain and biome generation, which also changed in 1.2 (only biomes and biome-dependent terrain, so you may not see sudden changes everywhere), 1.7 (completely changed), and probably a few times in InfDev-Beta).
i have one question what if i make a Minecraft world but then go into the folder delete the region folder and then replace it with a region folder of another world that has a completely different seed
i have one question what if i make a Minecraft world but then go into the folder delete the region folder and then replace it with a region folder of another world that has a completely different seed
This will work but newly generated chunks will be different, leading to sudden biome changes and cliffs between existing and new terrain, much like these examples (in these cases I actually loaded a modded world in vanilla, with the seed remaining the same, but the same applies to a different seed because each seed has different world generation even if the version remains the same):
In this case vanilla has ocean where the modded version has land, so new chunks (on the outside) were ocean:
In this case the modded version doubled the depth of the ground, leading to giant cliffs down to vanilla terrain, which was otherwise the same (much smaller cliffs will occur in worlds where the seed changed, though you could have a mountain biome cut off by an ocean, or a custom world which will take on the terrain of the new seed, e.g. a caves world type changing to floating islands):
The only thing that will change in already generated terrain is the locations of slime chunks (where slimes spawn underground), which are determined using the current seed, and for versions between 1.6.4-1.12.2, where the game thinks structures like strongholds are located (i.e. eyes of ender will lead you to where the game thinks they are based on the current seed and witches won't spawn in witch huts) if you don't copy over the structure data files in the data folder, which can also cause structures to generate in otherwise invalid locations, as shown in the second example above (the game saves structure data for all structures within 8 chunks of generated terrain and vanilla read the saved structure data from the modded version, placing them at impossible altitudes). Note that the data folder also stores map item data, which will cause maps to break unless you include the "idcounts.dat" and "map#.dat" files). Worlds in versions older than 1.2, or upgraded to newer versions, will also take on the biomes of the current seed (snowy biomes may have rain and vice-versa since it wasn't saved with the world until then, much like structure data prior to 1.6.4).
This will work but newly generated chunks will be different, leading to sudden biome changes and cliffs between existing and new terrain, much like these examples (in these cases I actually loaded a modded world in vanilla, with the seed remaining the same, but the same applies to a different seed because each seed has different world generation even if the version remains the same):
In this case vanilla has ocean where the modded version has land, so new chunks (on the outside) were ocean:
In this case the modded version doubled the depth of the ground, leading to giant cliffs down to vanilla terrain, which was otherwise the same (much smaller cliffs will occur in worlds where the seed changed, though you could have a mountain biome cut off by an ocean, or a custom world which will take on the terrain of the new seed, e.g. a caves world type changing to floating islands):
The only thing that will change in already generated terrain is the locations of slime chunks (where slimes spawn underground), which are determined using the current seed, and for versions between 1.6.4-1.12.2, where the game thinks structures like strongholds are located (i.e. eyes of ender will lead you to where the game thinks they are based on the current seed and witches won't spawn in witch huts) if you don't copy over the structure data files in the data folder, which can also cause structures to generate in otherwise invalid locations, as shown in the second example above (the game saves structure data for all structures within 8 chunks of generated terrain and vanilla read the saved structure data from the modded version, placing them at impossible altitudes). Note that the data folder also stores map item data, which will cause maps to break unless you include the "idcounts.dat" and "map#.dat" files). Worlds in versions older than 1.2, or upgraded to newer versions, will also take on the biomes of the current seed (snowy biomes may have rain and vice-versa since it wasn't saved with the world until then, much like structure data prior to 1.6.4).
also one question if i make a world in 1.6 and load it in beta 1.5 i know the chunks will be reset but will i still keep the items i have in my inventory
also one question if i make a world in 1.6 and load it in beta 1.5 i know the chunks will be reset but will i still keep the items i have in my inventory
Beta 1.5 can't read the region files used by 1.6, which have an entirely different extension (.mca for 1.6 and .mcr for Beta 1.5) so you'll actually end up with a world that has chunks from both versions (only one version will be able to read them though, and when upgrading the conversion process may overwrite the original .mca files, while leaving the original .mcr files intact so you can easily undo the upgrade).
As for your inventory, I don't think the format of level.dat changed much between Beta 1.5 and 1.6; the game used numerical IDs until 1.8 and while they added some new NBT data (e.g. gamerules and ender chest inventory to level.dat and inhabited time to chunks) this is completely ignored by older versions, the only potential issue is unknown item IDs (I don't know how they are handled by older versions or whether the invalid ID removal code was present back then). One thing that I do know is that unknown enchantments will crash the game (I once loaded a modded world in vanilla and the game crashed as soon as I moused over a Mending book, which doesn't exist in vanilla 1.6.4), but they didn't exist back in Beta 1.5 so they will probably disappear.
There is no way you could have possibly loaded a 1.16.4 world in 1.7.10 with no issues - try placing some blocks and they will disappear because the chunks will have been reset, which will also be obvious if you take screenshots before and after (trees, grass, flowers, etc will change because they are placed differently). Any items in your inventory will also disappear (same for any version after 1.7.10 since 1.8 changed all item IDs from numbers to text and 1.7.10 has no idea how to read them, much as 1.13 changed the way blocks are stored in chunks) so it will be as if you'd created a brand-new world - there is simply no way to downgrade past 1.13 and keep anything unless you use a special tool designed to convert save formats and I don't know of any such tools (either way, you still can't transfer over things that don't exist in the older version unless you use/make a mod that backports them but then you aren't really downgrading, or replace them with the closest substitute).
yes i now understand that downgrading is bad because if I load a 1.16.4 world in 1.7.10 it does not understand the text item ids and does not recognize the data version and it tries its best so the game does not crash and it ignores the data which is lost forever and also mojang said that downgrading is not was never and will never be supported
Beta 1.5 can't read the region files used by 1.6, which have an entirely different extension (.mca for 1.6 and .mcr for Beta 1.5) so you'll actually end up with a world that has chunks from both versions (only one version will be able to read them though, and when upgrading the conversion process may overwrite the original .mca files, while leaving the original .mcr files intact so you can easily undo the upgrade).
As for your inventory, I don't think the format of level.dat changed much between Beta 1.5 and 1.6; the game used numerical IDs until 1.8 and while they added some new NBT data (e.g. gamerules and ender chest inventory to level.dat and inhabited time to chunks) this is completely ignored by older versions, the only potential issue is unknown item IDs (I don't know how they are handled by older versions or whether the invalid ID removal code was present back then). One thing that I do know is that unknown enchantments will crash the game (I once loaded a modded world in vanilla and the game crashed as soon as I moused over a Mending book, which doesn't exist in vanilla 1.6.4), but they didn't exist back in Beta 1.5 so they will probably disappear.
yes i now understand that downgrading is bad because if I load a 1.16.4 world in 1.7.10 it does not understand the text item ids and does not recognize the data version and it tries its best so the game does not crash and it ignores the data which is lost forever and also mojang said that downgrading is not was never and will never be supported
i have one question what if i make a Minecraft world but then go into the folder delete the region folder and then replace it with a region folder of another world that has a completely different seed
This will work but newly generated chunks will be different, leading to sudden biome changes and cliffs between existing and new terrain, much like these examples (in these cases I actually loaded a modded world in vanilla, with the seed remaining the same, but the same applies to a different seed because each seed has different world generation even if the version remains the same):
In this case the modded version doubled the depth of the ground, leading to giant cliffs down to vanilla terrain, which was otherwise the same (much smaller cliffs will occur in worlds where the seed changed, though you could have a mountain biome cut off by an ocean, or a custom world which will take on the terrain of the new seed, e.g. a caves world type changing to floating islands):
The only thing that will change in already generated terrain is the locations of slime chunks (where slimes spawn underground), which are determined using the current seed, and for versions between 1.6.4-1.12.2, where the game thinks structures like strongholds are located (i.e. eyes of ender will lead you to where the game thinks they are based on the current seed and witches won't spawn in witch huts) if you don't copy over the structure data files in the data folder, which can also cause structures to generate in otherwise invalid locations, as shown in the second example above (the game saves structure data for all structures within 8 chunks of generated terrain and vanilla read the saved structure data from the modded version, placing them at impossible altitudes). Note that the data folder also stores map item data, which will cause maps to break unless you include the "idcounts.dat" and "map#.dat" files). Worlds in versions older than 1.2, or upgraded to newer versions, will also take on the biomes of the current seed (snowy biomes may have rain and vice-versa since it wasn't saved with the world until then, much like structure data prior to 1.6.4).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
also one question if i make a world in 1.6 and load it in beta 1.5 i know the chunks will be reset but will i still keep the items i have in my inventory
Beta 1.5 can't read the region files used by 1.6, which have an entirely different extension (.mca for 1.6 and .mcr for Beta 1.5) so you'll actually end up with a world that has chunks from both versions (only one version will be able to read them though, and when upgrading the conversion process may overwrite the original .mca files, while leaving the original .mcr files intact so you can easily undo the upgrade).
As for your inventory, I don't think the format of level.dat changed much between Beta 1.5 and 1.6; the game used numerical IDs until 1.8 and while they added some new NBT data (e.g. gamerules and ender chest inventory to level.dat and inhabited time to chunks) this is completely ignored by older versions, the only potential issue is unknown item IDs (I don't know how they are handled by older versions or whether the invalid ID removal code was present back then). One thing that I do know is that unknown enchantments will crash the game (I once loaded a modded world in vanilla and the game crashed as soon as I moused over a Mending book, which doesn't exist in vanilla 1.6.4), but they didn't exist back in Beta 1.5 so they will probably disappear.
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
yes i now understand that downgrading is bad because if I load a 1.16.4 world in 1.7.10 it does not understand the text item ids and does not recognize the data version and it tries its best so the game does not crash and it ignores the data which is lost forever and also mojang said that downgrading is not was never and will never be supported
yes i now understand that downgrading is bad because if I load a 1.16.4 world in 1.7.10 it does not understand the text item ids and does not recognize the data version and it tries its best so the game does not crash and it ignores the data which is lost forever and also mojang said that downgrading is not was never and will never be supported