feat: align all components to SemVer 2.0 for version comparison

src/c#/GeneralUpdate.Core/Configuration/AppMetadataDiscoverer.cs

@@ -30,7 +30,7 @@ public static void Discover(UpdateContext context)
         // otherwise the default blocks the manifest value and causes issues:
         //   • MainAppName "Client" → can't find the real executable
         //   • UpdateAppName "Update.exe" → can't launch the upgrade process
-        //   • ClientVersion "1.0.0.0" → endless update loop (version never updates)
+        //   • ClientVersion "1.0.0" → endless update loop (version never updates)
         if (!string.IsNullOrWhiteSpace(manifest.MainAppName))
             context.MainAppName = manifest.MainAppName;
         if (!string.IsNullOrWhiteSpace(manifest.UpdateAppName))

src/c#/GeneralUpdate.Core/Configuration/UpdateConfiguration.cs

@@ -108,7 +108,7 @@ public abstract class UpdateConfiguration
         ///     Comparing <c>ClientVersion</c> against the latest version from the server determines whether the
         ///     main application needs updating (<see cref="UpdateContext.IsMainUpdate" />).
         /// </remarks>
-        public string ClientVersion { get; set; } = "1.0.0.0";
+        public string ClientVersion { get; set; } = "1.0.0";
 
         /// <summary>
         ///     A list of specific files to exclude from the update process.

src/c#/GeneralUpdate.Core/Configuration/UpdateRequestBuilder.cs

@@ -82,7 +82,7 @@ public class UpdateRequestBuilder
         ///                 "Token": "mytoken",
         ///                 "Scheme": "https",
         ///                 "MainAppName": "MyApp",
-        ///                 "ClientVersion": "1.0.0.0"
+        ///                 "ClientVersion": "1.0.0"
         ///             }
         ///         </code>
         ///     </para>

src/c#/GeneralUpdate.Core/Configuration/VersionEntry.cs

@@ -84,7 +84,7 @@ public class VersionEntry : VersionIdentity
     public override string? Url { get; set; }
 
     /// <summary>
-    ///     The version number string of this version information (e.g., "1.0.0.1").
+    ///     The version number string of this version information (e.g., "1.0.0").
     /// </summary>
     [JsonPropertyName("version")]
     public override string? Version { get; set; }

src/c#/GeneralUpdate.Core/Configuration/VersionIdentity.cs

@@ -22,7 +22,7 @@ public abstract class VersionIdentity
     /// <summary>Download URL of the update package.</summary>
     public virtual string? Url { get; set; }
 
-    /// <summary>Version number string (e.g., "1.0.0.1").</summary>
+    /// <summary>Version number string (e.g., "1.0.0").</summary>
     public virtual string? Version { get; set; }
 
     /// <summary>Application type identifier.</summary>

src/c#/GeneralUpdate.Core/Download/DownloadPlanBuilder.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using GeneralUpdate.Core.Configuration;
 using GeneralUpdate.Core.Download.Models;
+using GeneralUpdate.Core.Utilities;
 
 namespace GeneralUpdate.Core.Download;
 
@@ -66,6 +67,7 @@ public static bool HasUpdate(
             .Where(a => (a.AppType ?? (int)AppType.Client) == (int)appType)
             .Select(a => ParseVersion(a.Version))
             .Where(v => v != null)
+            .Select(v => v!.Value)
             .ToList();
 
         if (serverVersions.Count == 0)
@@ -74,11 +76,11 @@ public static bool HasUpdate(
         // If the local version cannot be read or parsed, we can't prove we're
         // up to date — err on the side of updating rather than silently skipping.
         if (string.IsNullOrWhiteSpace(localVersion)
-            || !Version.TryParse(localVersion, out var local))
+            || !Semver.TryParse(localVersion, out var local))
             return true;
 
         // Compare: max server version > local version?
-        return serverVersions.Max()! > local;
+        return serverVersions.Max() > local;
     }
 
     /// <summary>
@@ -100,8 +102,10 @@ public static DownloadPlan Build(
         if (assets == null) return DownloadPlan.Empty;
         var parsedClient = ParseVersion(clientVersion);
         if (parsedClient == null) return DownloadPlan.Empty;
+        var cv = parsedClient.Value;
 
         var parsedUpgrade = ParseVersion(upgradeClientVersion) ?? parsedClient;
+        var uv = parsedUpgrade.Value;
 
         // 1. Filter out frozen packages
         var active = assets
@@ -118,17 +122,16 @@ public static DownloadPlan Build(
         var candidates = active
             .Where(a =>
             {
-                var pv = ParseVersion(a.Version);
-                if (pv == null) return false;
+                if (!Semver.TryParse(a.Version, out var pv)) return false;
 
                 var localVersion = (a.AppType == (int)AppType.Upgrade)
-                    ? parsedUpgrade
-                    : parsedClient;
+                    ? uv
+                    : cv;
 
                 return pv > localVersion;
             })
             .Where(a => IsCompatible(a.MinClientVersion, clientVersion))
-            .OrderBy(a => ParseVersion(a.Version))
+            .OrderBy(a => { Semver.TryParse(a.Version, out var sv); return sv; })
             .ToList();
 
         if (candidates.Count == 0) return DownloadPlan.Empty;
@@ -142,28 +145,27 @@ public static DownloadPlan Build(
             .Where(a => a.IsCrossVersion)
             .Where(a =>
             {
-                var fromVer = ParseVersion(a.FromVersion);
-                if (fromVer == null) return false;
+                if (!Semver.TryParse(a.FromVersion, out var fromVer)) return false;
                 var localVersion = (a.AppType == (int)AppType.Upgrade)
-                    ? parsedUpgrade
-                    : parsedClient;
+                    ? uv
+                    : cv;
                 return fromVer == localVersion;
             })
-            .OrderByDescending(a => ParseVersion(a.Version))
+            .OrderByDescending(a => { Semver.TryParse(a.Version, out var sv); return sv; })
             .FirstOrDefault();
 
         if (matchingCvp != null)
         {
             // CVP covers one AppType in a single hop. Still need chain packages
             // for other AppTypes, and for the same AppType beyond the CVP's target.
             var cvpAppType = matchingCvp.AppType;
-            var cvpVersion = ParseVersion(matchingCvp.Version);
+            Semver.TryParse(matchingCvp.Version, out var cvpVersion);
             var planAssets = new List<DownloadAsset> { matchingCvp };
             planAssets.AddRange(candidates
                 .Where(a => !a.IsCrossVersion)
                 .Where(a => a.AppType != cvpAppType
-                            || (cvpVersion != null && ParseVersion(a.Version) > cvpVersion))
-                .OrderBy(a => ParseVersion(a.Version)));
+                            || (Semver.TryParse(a.Version, out var av) && av > cvpVersion))
+                .OrderBy(a => { Semver.TryParse(a.Version, out var sv); return sv; }));
             return new DownloadPlan(planAssets, isForcibly);
         }
 
@@ -197,15 +199,15 @@ internal static bool IsCompatible(string? minClientVersion, string currentVersio
         var min = ParseVersion(minClientVersion);
         var cur = ParseVersion(currentVersion);
         if (min == null || cur == null) return true;
-        return cur >= min;
+        return cur.Value >= min.Value;
     }
 
     /// <summary>Parses a version string and returns null if the string cannot be parsed.</summary>
     /// <param name="version">The version string to parse.</param>
-    /// <returns>A parsed <see cref="Version"/> object, or null if parsing fails.</returns>
-    internal static Version? ParseVersion(string? version)
+    /// <returns>A parsed <see cref="SemVersion"/> value, or null if parsing fails.</returns>
+    internal static SemVersion? ParseVersion(string? version)
     {
         if (string.IsNullOrWhiteSpace(version)) return null;
-        return Version.TryParse(version, out var v) ? v : null;
+        return Semver.TryParse(version, out var v) ? v : null;
     }
 }

src/c#/GeneralUpdate.Core/Strategy/ClientStrategy.cs

@@ -13,6 +13,7 @@
 using GeneralUpdate.Core.JsonContext;
 using GeneralUpdate.Core.Ipc;
 using GeneralUpdate.Core.Pipeline;
+using GeneralUpdate.Core.Utilities;
 
 namespace GeneralUpdate.Core.Strategy;
 
@@ -943,16 +944,16 @@ private bool CanSkip(bool isForcibly, UpdateInfoEventArgs updateInfo)
     /// <remarks>
     /// Reads the known failed version number from the <c>UpgradeFail</c> environment variable.
     /// If the <c>UpgradeFail</c> environment variable is empty or <paramref name="version"/> is empty, returns <c>false</c>.
-    /// Version comparison uses the semantic version comparison of the <see cref="Version"/> class.
+    /// Version comparison uses the semantic version comparison of the <see cref="Semver"/> class.
     /// This mechanism avoids repeatedly attempting known failed upgrades.
     /// </remarks>
     private bool CheckFail(string version)
     {
         var fail = Environments.GetEnvironmentVariable("UpgradeFail");
         if (string.IsNullOrEmpty(fail) || string.IsNullOrEmpty(version))
             return false;
-        if (!Version.TryParse(fail, out var failVersion) ||
-            !Version.TryParse(version, out var versionParsed))
+        if (!Semver.TryParse(fail, out var failVersion) ||
+            !Semver.TryParse(version, out var versionParsed))
             return false;
         return failVersion >= versionParsed;
     }

src/c#/GeneralUpdate.Core/Strategy/OssStrategy.cs

@@ -12,6 +12,7 @@
 using GeneralUpdate.Core.Download.Abstractions;
 using GeneralUpdate.Core.Download.Models;
 using GeneralUpdate.Core.Download.Orchestrators;
+using GeneralUpdate.Core.Utilities;
 
 namespace GeneralUpdate.Core.Strategy;
 
@@ -350,7 +351,12 @@ private async Task ExecuteUpgradeAsync()
                     throw new InvalidOperationException("No versions found in Oss configuration.");
 
                 assets = versions.OrderBy(v => v.PubTime)
-                    .Where(v => new Version(v.Version ?? "0.0.0") > new Version(_configInfo.ClientVersion))
+                    .Where(v =>
+                    {
+                        var sv = ParseSemVer(v.Version);
+                        var cv = ParseSemVer(_configInfo.ClientVersion);
+                        return sv != null && cv != null && sv.Value > cv.Value;
+                    })
                     .Select(v =>
                     {
                         if (string.IsNullOrWhiteSpace(v.Url))
@@ -366,12 +372,17 @@ private async Task ExecuteUpgradeAsync()
             if (assets.Count == 0)
                 throw new InvalidOperationException("No assets to download.");
 
-            // Compute LastVersion deterministically via Version comparison
+            // Compute LastVersion deterministically via SemVer comparison
             // so hooks see the correct TargetVersion regardless of source ordering.
-            _configInfo.LastVersion = assets
-                .Select(a => new Version(a.Version))
-                .Max()!
-                .ToString();
+            // Guard: if ALL versions are unparseable, fall back to "0.0.0".
+            var parsedVersions = assets
+                .Select(a => Semver.TryParse(a.Version, out var sv) ? (SemVersion?)sv : null)
+                .Where(sv => sv != null)
+                .Select(sv => sv!.Value)
+                .ToList();
+            _configInfo.LastVersion = parsedVersions.Count > 0
+                ? parsedVersions.Max().ToString()
+                : "0.0.0";
             ctx = BuildUpdateContext();
 
             // Hooks: allow cancellation before download. Called after assets are
@@ -483,15 +494,15 @@ private static async Task DownloadVersionConfig(string url, string path)
     /// <param name="serverVersion">The latest server version string.</param>
     /// <returns>Returns true if the server version is higher than the client version; otherwise false.</returns>
     /// <remarks>
-    /// This method attempts to parse both version strings as <c>Version</c> types for comparison.
+    /// This method attempts to parse both version strings as SemVer 2.0 for comparison.
     /// If either version string is null, empty, or cannot be parsed, returns false indicating no upgrade is needed.
     /// </remarks>
     private static bool IsOssUpgrade(string clientVersion, string serverVersion)
     {
         if (string.IsNullOrWhiteSpace(clientVersion) || string.IsNullOrWhiteSpace(serverVersion))
             return false;
-        return Version.TryParse(clientVersion, out var cv)
-            && Version.TryParse(serverVersion, out var sv)
+        return Semver.TryParse(clientVersion, out var cv)
+            && Semver.TryParse(serverVersion, out var sv)
             && cv < sv;
     }
 
@@ -655,5 +666,13 @@ private async Task SafeReportUpdateFailedAsync(Hooks.HookContext ctx, Exception
         catch (Exception ex) { GeneralTracer.Warn($"Report UpdateFailed failed: {ex.Message}"); }
     }
 
+    /// <summary>
+    /// Lightweight SemVer parse guard that returns null (not an exception) for unparseable strings.
+    /// </summary>
+    private static SemVersion? ParseSemVer(string? version)
+    {
+        return Semver.TryParse(version, out var sv) ? sv : null;
+    }
+
     #endregion
 }