From d9f28c5b2a75012c27af13970a311357e6163d87 Mon Sep 17 00:00:00 2001
From: RedBlackAka <140876408+RedBlackAka@users.noreply.github.com>
Date: Tue, 10 Mar 2026 17:01:40 +0100
Subject: [PATCH] Qt: Improve update checker system to prevent downgrades #1749
 (#1768)

* Qt: Improve update checker system to prevent downgrades

* Code cleanup

* Return 0 as fallback

* Satisfy clang-format

---------

Co-authored-by: OpenSauce04 <opensauce04@gmail.com>
---
 src/citra_qt/citra_qt.cpp | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/citra_qt/citra_qt.cpp b/src/citra_qt/citra_qt.cpp
index cf689ec03..242fab411 100644
--- a/src/citra_qt/citra_qt.cpp
+++ b/src/citra_qt/citra_qt.cpp
@@ -180,12 +180,21 @@ bool IsPrereleaseBuild() {
 }
 
 #ifdef ENABLE_QT_UPDATE_CHECKER
-bool ShouldCheckForPrereleaseUpdates() {
+static bool ShouldCheckForPrereleaseUpdates() {
     const bool update_channel = UISettings::values.update_check_channel.GetValue();
     const bool using_prerelease_channel =
         (update_channel == UISettings::UpdateCheckChannels::PRERELEASE);
     return (IsPrereleaseBuild() || using_prerelease_channel);
 }
+
+static int GetMajorVersion(const std::string& version) {
+    size_t dot = version.find('.');
+    try {
+        return std::stoi(version.substr(0, dot));
+    } catch (...) {
+        return 0;
+    }
+}
 #endif
 
 GMainWindow::GMainWindow(Core::System& system_)
@@ -422,7 +431,11 @@ GMainWindow::GMainWindow(Core::System& system_)
                 UpdateChecker::GetLatestRelease(ShouldCheckForPrereleaseUpdates());
 
             if (latest_release_tag && latest_release_tag.value() != Common::g_build_fullname) {
-                return QString::fromStdString(latest_release_tag.value());
+                const int latest_major_version = GetMajorVersion(latest_release_tag.value());
+                const int current_major_version = GetMajorVersion(Common::g_build_fullname);
+                if (current_major_version <= latest_major_version) {
+                    return QString::fromStdString(latest_release_tag.value());
+                }
             }
             return QString{};
         });