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Krypton

Krypton

by astei • Downloads: 0 • Followers: 0
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Warning

I do not provide any guarantees about Krypton's stability, compatibility with other mods, or support for every possible setup out there.

Support for this mod is provided on a "best-effort" basis.

I have held down a very demanding job since November 2021. I consider this mod to be effectively feature-stable and will generally only provide updates for new Minecraft versions on an as-needed basis, based on my personal availability.

Don't ask if you can adopt this mod. I've done this few times before. It has not gone well, so don't ask.

What's Krypton?

Krypton (from Ancient Greek kryptos, "the hidden one") is a Fabric mod that attempts to optimize the Minecraft networking stack. It derives from work done in the Velocity and Tuinity projects.

Krypton contains several optimizations, including:

  • Highly optimized Netty handlers derived from the Velocity proxy, which I am the developer of. These handlers have seen real-world usage and extensive profiling, and strategically deploy native code where it makes the most sense.
  • Flush consolidation to lower server CPU usage (and reducing the impact from hardware security vulnerabilities which exploit speculative execution) and lower server tick times.
  • Micro-optimizations to reduce memory usage and improve packet serialization speeds.

Compatibility

Krypton should work anywhere where a Minecraft can run — naturally, however, it is tuned for Linux.

I try to ensure that Krypton will work with the Fabric API, Lithium, and Sodium. Support beyond these mods is provided on a best effort basis.

All Versions

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Name Game version Platforms Published Downloads Actions
26.3
Fabric
23h ago 1
26.2
Fabric
23h ago 1
26.1.x
Fabric
23h ago 1
1.21.x
Fabric
23h ago 1
1.21.x
Fabric
23h ago 1
1.21.x
Fabric
23h ago 1
1.20.x
Fabric
23h ago 1
1.20.x
Fabric
23h ago 1
1.20.x
Fabric
23h ago 1
1.20.x
Fabric
23h ago 1
1.20.x
Fabric
23h ago 1
1.19.4
Fabric
23h ago 1
1.19.x
Fabric
23h ago 1
1.19
Fabric
23h ago 1
1.18.x
Fabric
23h ago 1
1.18.x
Fabric
23h ago 1
1.18.1
Fabric
23h ago 1
26.3 26.2 26.1.x +6
Fabric
23h ago 1
1.17.1
Fabric
23h ago 1
1.17
Fabric
23h ago 1
1.16.x
Fabric
23h ago 1
1.16.x
Fabric
23h ago 1
1.16.x
Fabric
23h ago 1
[0.3.2] Krypton 0.3.2 by astei on Oct 07, 2026
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  • Update for Minecraft 26.3
  • Change how encryption is injected. This improves compatibility with other mods that modify the login process. Notably, this makes e4mc work.
[0.3.1] Krypton 0.3.1 by astei on Oct 07, 2026
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  • Update for Minecraft 26.2
[0.3.0] Krypton 0.3.0 by astei on Oct 07, 2026
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  • Update to Minecraft 26.1

Sorry for the delay. My real life job leaves little time for Minecraft.
[0.2.10] Krypton 0.2.10 by astei on Oct 07, 2026
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  • Update for Minecraft 1.21.9
[0.2.9] Krypton 0.2.9 by astei on Oct 07, 2026
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  • Update to Minecraft 1.21.5
  • Resync network handlers from upstream

[0.2.8] Krypton 0.2.8 by astei on Oct 07, 2026
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  • Update to 1.21 (@BenCat07)
[0.2.7] Krypton 0.2.7 by astei on Oct 07, 2026
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  • Update for Minecraft 1.20.5/1.20.6
[0.2.6] Krypton 0.2.6 by astei on Oct 07, 2026
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  • Fixes a memory leak.
[0.2.5] 0.2.5 by astei on Oct 07, 2026
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  • Fixes an incompatibility with Fabric API 0.9.1 and above. See also #111
  • Resync compress handler with Velocity
[0.2.4] 0.2.4 by astei on Oct 07, 2026
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  • Updated to Minecraft 1.20.2
  • Add krypton.permit-oversized-packets system property to permit oversized packets. Defaults to false for security reasons.
[0.2.3] 0.2.3 by astei on Oct 07, 2026
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  • Updated to Minecraft 1.20
  • Removed a mixin that is now implemented in the base game
  • Improved protocol conformance - Krypton now handles servers dynamically disabling and re-enabling compression
  • Added events indicating when certain events in the network pipeline happen that mods can snoop on
  • As a consequence of this, the old ViaFabric hooks have been removed.
[0.2.2] 0.2.2 by astei on Oct 07, 2026
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Thanks to DrexHD for the update to Minecraft 1.19.4!

  • Update to Minecraft 1.19.4
  • Updated velocity-native
[0.2.1] 0.2.1 by astei on Oct 07, 2026
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  • Update to Minecraft 1.19.1 (contributed by @wafflecoffee)
  • Fixed Multiconnect mod compatibility
[0.2.0] 0.2.0 by astei on Oct 07, 2026
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This is not just a Minecraft 1.19 update, it's also a feature release!

  • Fixes crash with Lithium on Quilt
  • Resynced with latest Velocity code
  • Send chunk packets in a spiral pattern and other fixes (contributed by @solonovamax)

[0.1.9] 0.1.9 by astei on Oct 07, 2026
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Fixes a regression with 0.1.8.
[0.1.7] 0.1.7 by astei on Oct 07, 2026
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Fix compatibility with 1.18.2
[0.1.6] 0.1.6 by astei on Oct 07, 2026
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  • Updated to Minecraft 1.18.1
[0.1.5] 0.1.5 by astei on Oct 07, 2026
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  • Updated to Minecraft 1.18
  • Fixed connecting to certain misbehaving server implementations
  • Added optimizations for the Minecraft entity tracker:
  • Optimized passenger check for the common case where there are no passengers riding an entity.
  • Optimized chunk sending to only track entities the player is nearby to
[0.1.4] 0.1.4 by astei on Oct 07, 2026
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Compatible with Minecraft 1.17.1
[0.1.3] 0.1.3 by astei on Oct 07, 2026
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  • Updated to Minecraft 1.17. (This release is not compatible with Minecraft 1.16.5 and earlier.)
  • Added VarInt writing optimizations.
  • Fixed packet sending counter.
  • Fixed ViaFabric incompatibility.
[0.1.2] 0.1.2 by astei on Oct 07, 2026
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Fixed several issues with flush consolidation
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