diff --git a/Sources/ClaudeUsageMonitor/App/BundleConfiguration.swift b/Sources/ClaudeUsageMonitor/App/BundleConfiguration.swift
index bbb5fae..931ce24 100644
--- a/Sources/ClaudeUsageMonitor/App/BundleConfiguration.swift
+++ b/Sources/ClaudeUsageMonitor/App/BundleConfiguration.swift
@@ -18,6 +18,16 @@ enum BundleConfiguration {
     }
 
     static var ccusageVersion: String {
-        return Bundle.main.object(forInfoDictionaryKey: "CcusageVersion") as? String ?? ""
+        let version = Bundle.main.object(forInfoDictionaryKey: "CcusageVersion") as? String ?? ""
+        let fallbackVersion = "15.3.0"
+        
+        // Debug時にInfo.plistが更新されていない場合のフォールバック
+        if version.isEmpty {
+            print("⚠️ [BundleConfiguration] CcusageVersion not found in Info.plist, using fallback: \(fallbackVersion)")
+            return fallbackVersion
+        }
+        
+        print("📦 [BundleConfiguration] Using ccusage version: \(version)")
+        return version
     }
 }
diff --git a/Sources/ClaudeUsageMonitor/Services/CommandExecutor.swift b/Sources/ClaudeUsageMonitor/Services/CommandExecutor.swift
index a8c745d..5340e66 100644
--- a/Sources/ClaudeUsageMonitor/Services/CommandExecutor.swift
+++ b/Sources/ClaudeUsageMonitor/Services/CommandExecutor.swift
@@ -74,18 +74,23 @@ class CommandExecutor {
     func executeCcusageCommand(subcommand: String? = nil, additionalArgs: [String] = []) async throws -> String {
         var command: String
         var ccusageArgs: [String] = []
+        
+        let ccusageVersion = BundleConfiguration.ccusageVersion
+        guard !ccusageVersion.isEmpty else {
+            throw CommandError.commandNotFound("ccusage version not configured")
+        }
 
         // Try bunx first
         if let bunxPath = try await findCommand("bunx") {
             print("[CommandExecutor] Found bunx at: \(bunxPath)")
             command = bunxPath
-            ccusageArgs.append("ccusage@\(BundleConfiguration.ccusageVersion)")
+            ccusageArgs.append("ccusage@\(ccusageVersion)")
         }
         // Fall back to npx
         else if let npxPath = try await findCommand("npx") {
             print("[CommandExecutor] Found npx at: \(npxPath)")
             command = npxPath
-            ccusageArgs.append("ccusage@\(BundleConfiguration.ccusageVersion)")
+            ccusageArgs.append("ccusage@\(ccusageVersion)")
         }
         // Neither found
         else {
@@ -103,6 +108,7 @@ class CommandExecutor {
         ccusageArgs.append(contentsOf: additionalArgs)
 
         print("[CommandExecutor] Executing: \(command) \(ccusageArgs.joined(separator: " "))")
+        print("[CommandExecutor] Using ccusage version: \(ccusageVersion)")
 
         // Execute the command
         let task = Process()
diff --git a/Sources/ClaudeUsageMonitor/ViewModels/SessionViewModel.swift b/Sources/ClaudeUsageMonitor/ViewModels/SessionViewModel.swift
index 46b0c49..27a6b20 100644
--- a/Sources/ClaudeUsageMonitor/ViewModels/SessionViewModel.swift
+++ b/Sources/ClaudeUsageMonitor/ViewModels/SessionViewModel.swift
@@ -26,13 +26,17 @@ class SessionViewModel: ObservableObject {
         }
 
         session = data
-        remainingTokens = monitor.usageData.sessionTokenLimit - data.totalTokens
+        remainingTokens = max(0, monitor.usageData.sessionTokenLimit - data.totalTokens)
         percentage = monitor.usageData.sessionUsagePercentage
         burnRate = Double(monitor.usageData.sessionBurnRate) ?? 0
         remainingTime = monitor.usageData.sessionRemainingTime
         cost = data.costUSD
         planDescription = monitor.usageData.planDescription
         resetTime = Date.formatTime(from: data.endTime)
+        
+        // デバッグ用ログ
+        print("🔍 [SessionViewModel] Total: \(data.totalTokens), Limit: \(monitor.usageData.sessionTokenLimit), Remaining: \(remainingTokens)")
+        print("🔍 [SessionViewModel] Plan: \(planDescription), Percentage: \(String(format: "%.1f", percentage))%")
 
         // 通知機能は初回リリースでは無効化
         /*
diff --git a/Sources/ClaudeUsageMonitor/Views/Tabs/SettingsTabView.swift b/Sources/ClaudeUsageMonitor/Views/Tabs/SettingsTabView.swift
index 5399b9d..55667c5 100644
--- a/Sources/ClaudeUsageMonitor/Views/Tabs/SettingsTabView.swift
+++ b/Sources/ClaudeUsageMonitor/Views/Tabs/SettingsTabView.swift
@@ -580,10 +580,15 @@ struct SettingsTabView: View {
     private func selectUpdateChannel(_ channel: UpdateChannel) {
         UserDefaults.standard.updateChannel = channel
         
+        #if canImport(Sparkle)
         // Notify AppDelegate to update Sparkle configuration
         if let appDelegate = NSApplication.shared.delegate as? AppDelegate {
             appDelegate.updateChannelChanged(to: channel)
         }
+        #endif
+        
+        // Re-fetch latest versions when channel changes
+        fetchLatestVersions()
     }
     
     private func checkLatestVersion() {
@@ -628,10 +633,13 @@ struct SettingsTabView: View {
     }
     
     private func fetchLatestVersions() {
+        print("🔄 Starting to fetch latest versions...")
+        
         // Fetch stable version
         Task {
             await fetchLatestVersion(for: .stable) { version in
                 self.latestStableVersion = version
+                print("📦 Stable version set to: \(version ?? "nil")")
             }
         }
         
@@ -639,28 +647,55 @@ struct SettingsTabView: View {
         Task {
             await fetchLatestVersion(for: .dev) { version in
                 self.latestDevVersion = version
+                print("📦 Dev version set to: \(version ?? "nil")")
             }
         }
     }
     
     private func fetchLatestVersion(for channel: UpdateChannel, completion: @escaping (String?) -> Void) async {
         guard let url = URL(string: channel.appcastURL) else {
+            print("❌ Invalid URL for channel \(channel): \(channel.appcastURL)")
             completion(nil)
             return
         }
         
         do {
-            let (data, _) = try await URLSession.shared.data(from: url)
+            let (data, response) = try await URLSession.shared.data(from: url)
+            
+            if let httpResponse = response as? HTTPURLResponse {
+                print("📡 Fetching \(channel) version from: \(url)")
+                print("📡 Response status: \(httpResponse.statusCode)")
+                
+                guard httpResponse.statusCode == 200 else {
+                    print("❌ HTTP error: \(httpResponse.statusCode)")
+                    await MainActor.run {
+                        completion(nil)
+                    }
+                    return
+                }
+            }
+            
             let parser = XMLParser(data: data)
             let delegate = AppcastParserDelegate()
             parser.delegate = delegate
             
             if parser.parse(), let version = delegate.latestVersion {
+                print("✅ Found \(channel) version: \(version)")
                 await MainActor.run {
                     completion(version)
                 }
+            } else {
+                print("❌ Failed to parse XML for \(channel)")
+                // デバッグ用: XMLの最初の部分を表示
+                if let xmlString = String(data: data.prefix(500), encoding: .utf8) {
+                    print("XML preview: \(xmlString)")
+                }
+                await MainActor.run {
+                    completion(nil)
+                }
             }
         } catch {
+            print("❌ Error fetching \(channel) version: \(error)")
             await MainActor.run {
                 completion(nil)
             }