In 2020, I had the idea to port Beta 1.7.3 (released on July 8th 2011), that runs on a more dated version of Minecraft's engine, with less mod support and lacking features that are convenient today like Creative Mode, to 1.12.2 (released on September 18th 2017). This is a far more modern version of the engine, and many mods made nowadays still support this version.

You could then play 1.7.3 with better mod support, Hardcore Mode, 256 block height limit (in Beta this was restricted to 128), Creative Mode, etc. The porting was close to complete in early 2021, the only thing that was missing were the achievements and some visual changes.

From early 2021 onwards, I decided to add a lot of popular mods, such as Bloodmoon, Hwyla, Serene Seasons, and JEI. What we now have is an almost direct port of 1.7.3 in the 1.12.2 client with extra mods added.

The current version was released on July 8th 2011, 10 years after Beta 1.7.3 was released to the public. Certain things like the 1.7.3 achievements have not been ported over, and there are some slight visual changes. This may be changed in later updates.

I hope you enjoy my modpack!

Summary:

Beta One Twelve aims to bring Beta 1.7.3 as closely as possible to the 1.12.2 client, while at the same time, the modpack aims to add all kinds of improvements to gameplay. From QoL features, to better graphics, better mob AI, and in-game events like Bloodmoon to make the game more challenging.

If you want the game to feel like a direct remake, with few improvements, then you should download 1.03b. If you want some extra features that still keep gameplay authentic, but less so, then you should download the latest version.

Beta One Twelve is a part of The One Twelve series of modpacks alongside Alpha One Twelve. For fans of the Alpha versions, I would highly recommend you try out Alpha One Twelve.

Features:

Beta 1.7.3 in 1.12.2

Almost 100% identical looking terrain to Beta 1.7.3!
Crafting recipes.
Textures and sounds.
2D bow and arrow.
Diamond sword with an attack damage of 10!
No more attack cooldowns or sword sweeps.
No more hunger and experience.
Accurate Beta 1.7.3 mob drops.

Additional mods

Seasons. Foliage and grass colours change every season, and snow and ice generate in the colder seasons.
Many quality-of-life mods, like Hwyla, Just Enough Items, Inventory Tweaks, AutoWalk, Carry On.
Increased difficulty with the Epic Siege & Bloodmoon mods.
Biome shading, Ambient Sounds, Dynamic Surroundings, Sound Filters and more.
Two new mobs have been added that fit in seemlessly with vanilla, the Bird and the Fish.
Easter Eggs! You can now dye cooked eggs, an edible version of the normal egg. About 100 combinations are possible.

Here is a gameplay video, and a comparison for those that are interested:

If you want a mod that only adds Beta-style generation but for 1.16/1.17 and does not remove modern structures, I highly recommend the Modern Beta mod by b3spectacled! But this modpack uses NostalgiaGen by Minecrell, and the CurseForge release by Skywalked.