Cobblemon Kotlin Patcher
by Tsubame
Cobblemon Kotlin Patcher is a Fabric management mod for Minecraft 1.20.1 that changes which Kotlin build the Cobblemon jar loads, so other mods that rely on a newer Kotlin can run beside it.
What it does
The patcher is meant to make Cobblemon on 1.20.1 work with mods that depend on a later Kotlin version than the one Cobblemon is packaged with. The author describes it as a workaround for a conflict that arose when Create 6.0 and its Estrogen dependency, together with the Cynosure library, needed a newer Kotlin than Cobblemon shipped.
The mod works on the client and on the server, and both sides need it when it is used. It is published for Fabric only and covers the single game version 1.20.1. The files are released as a beta channel build, and the code is licensed under the MIT License, but the project is not open source.
The author states they are new to Minecraft mod development and that the approach is a likely imperfect solution, so it should be tested before use on a shared world. Build 1.2 for 1.20.1 is the latest file, dated 2026-03-12.
Key features
Kotlin version swap
The patcher changes the Kotlin build that Cobblemon loads, letting mods that need a later Kotlin run in the same instance.
Disable and re-enable Cobblemon
Cobblemon can be disabled from the patcher, then enabled again by restoring its main mod jar, which the author describes as a reversible step.
Startup popup for Cobblemon addons
When other Cobblemon addons are present and the patcher is enabled, the game shows a popup on launch instead of starting normally.
Relaunch after first run
The first launch with the mod installed requires the game to be started again before the change takes effect.
Keep-disabled option
A setting keeps Cobblemon disabled between launches, so the original jar is not restored until the user chooses to re-enable it.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Running Create 6.0 with Cobblemon
Players who want Create 6.0 alongside Cobblemon on 1.20.1 can use the patcher to reconcile the Kotlin requirement that the author describes.
Who it’s for: Players and server owners on Fabric 1.20.1 who run Cobblemon with other mods that need a newer Kotlin, and who are willing to test a beta patch on a copy of their world first.
Questions
Does Cobblemon Kotlin Patcher need to be installed on the server?
Which loader does Cobblemon Kotlin Patcher support?
What should be done before enabling the patcher with other Cobblemon addons?
In the catalog
Cobblemon Kotlin Patcher is one of 8,016 Management mods on ModsFinder, and one of 5,930 Management mods for Fabric. 34,764 mods support Minecraft 1.20.1.
More from Tsubame
Similar mods
What the author says
WARNING: Disable Cobblemon! Keep it disabled! Launch the game again after it's first ever launch with this mod. This mod intends to make 1.20.1 Cobblemon compatible with other mods that rely on a newer version of Kotlin than Cobblemon was packaged with.
Official listing
- Modrinth page
- modrinth.com/mod/cobblemon-kotlin-patcher
- Owner
- Tsubame
- Published
- 2026-03-10
- Updated on Modrinth
- 2026-03-12
- Facts verified
- 2026-10-15