From 90deb7310e673addbf3cd2c0d70da3fab1e44867 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois-Xavier=20Talbot?=
 <108630700+fetchfern@users.noreply.github.com>
Date: Mon, 30 Mar 2026 13:53:29 -0400
Subject: [PATCH] Fix daedalus NeoForge (#5713)

* Support NeoForge version for year-based Minecraft versions

* Run on CI

* Fix

* Fix branch

* Undo branch switch
---
 apps/daedalus_client/src/error.rs |  2 ++
 apps/daedalus_client/src/forge.rs | 36 ++++++++++++++++++++++++-------
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/apps/daedalus_client/src/error.rs b/apps/daedalus_client/src/error.rs
index 586c7fc56..676534138 100644
--- a/apps/daedalus_client/src/error.rs
+++ b/apps/daedalus_client/src/error.rs
@@ -33,6 +33,8 @@ pub enum ErrorKind {
     Tracing(#[from] tracing::subscriber::SetGlobalDefaultError),
     #[error("Zip error: {0}")]
     Zip(#[from] async_zip::error::ZipError),
+    #[error("Failed to parse an integer: {0}")]
+    ParseIntError(#[from] std::num::ParseIntError),
 }
 
 #[derive(Debug)]
diff --git a/apps/daedalus_client/src/forge.rs b/apps/daedalus_client/src/forge.rs
index 1549f186c..3e9293281 100644
--- a/apps/daedalus_client/src/forge.rs
+++ b/apps/daedalus_client/src/forge.rs
@@ -141,9 +141,16 @@ pub async fn fetch_neo(
     }).chain(neo_versions.versioning.versions.version.into_iter().map(|loader_version| {
         let mut parts = loader_version.split('.');
 
-        // NeoForge Forge versions are in this format: 20.2.29-beta, 20.6.119
-        // Where the first number is the major MC version, the second is the minor MC version, and the third is the NeoForge version
-        let major = parts.next().ok_or_else(
+        // NeoForge Forge versions are in either of these formats:
+		// - 20.2.29-beta, 20.6.119
+		// - 26.1.0.10-beta, 26.1.0.16
+        //
+		// The first format is the "modern" format for Minecraft versions starting with 1, where the first number is the major MC version,
+		// the second is the minor MC version, and the third is the NeoForge version.
+		//
+		// The second format is the "new-modern" format for Minecraft versions in year-based format, where the first three numbers
+		// are the Minecraft version (year.release.hotfix), and the fourth, the NeoForge release version, with an optional "beta" suffix.
+        let major_or_year = parts.next().ok_or_else(
             || crate::ErrorKind::InvalidInput(format!("Unable to find major game version for NeoForge {loader_version}"))
         )?;
 
@@ -151,11 +158,24 @@ pub async fn fetch_neo(
             || crate::ErrorKind::InvalidInput(format!("Unable to find minor game version for NeoForge {loader_version}"))
         )?;
 
-        let game_version = if minor == "0" {
-            format!("1.{major}")
-        } else {
-            format!("1.{major}.{minor}")
-        };
+		let major_or_year = major_or_year.parse::<u32>()?;
+
+		// Year-based MC versions started in 2026
+		let game_version = match major_or_year {
+			26.. => {
+				let hotfix = parts.next().ok_or_else(
+					|| crate::ErrorKind::InvalidInput(format!("Unable to find hotfix version for NeoForge {loader_version}"))
+				)?;
+
+				if hotfix == "0" {
+					format!("{major_or_year}.{minor}")
+				} else {
+					format!("{major_or_year}.{minor}.{hotfix}")
+				}
+			}
+			..26 if minor == "0" => format!("1.{major_or_year}"),
+			..26 => format!("1.{major_or_year}.{minor}"),
+		};
 
         Ok(ForgeVersion {
             format_version: 2,