add properties for IsLive and IsLegacy

EDPlayerJournal/Entries/FileHeaderEntry.cs

@@ -26,6 +26,22 @@ public class FileHeaderEntry : Entry {
     /// </summary>
     public string? Build { get; set; }
 
+    /// <summary>
+    /// Returns true if the version is legacy (3.X)
+    /// <summary>
+    public bool IsLegacy {
+        get {
+            return GameVersion.StartsWith("3.");
+        }
+    }
+
+    /// <summary>
+    /// Returns true if the version is live (4.x)
+    /// </summary>
+    public bool IsLive {
+        get { return !IsLegacy; }
+    }
+
     protected override void Initialise() {
         Part = JSON.Value<ulong?>("part") ?? 1;
         Language = JSON.Value<string?>("language") ?? string.Empty;

EDPlayerJournalTests/FileHeaderTest.cs

@@ -21,6 +21,8 @@ public class FileHeaderTest {
         Assert.AreEqual(header.Language, "English/UK");
         Assert.AreEqual(header.Odyssey, true);
         Assert.AreEqual(header.GameVersion, "4.0.0.1450");
+        Assert.AreEqual(header.IsLegacy, false);
+        Assert.AreEqual(header.IsLive, true);
         // Someone at FDev messed up string building there.
         Assert.AreEqual(header.Build, "r286858/r0 ");
     }
@@ -44,6 +46,8 @@ public class FileHeaderTest {
         Assert.AreEqual(header.Language, """English\UK""");
         Assert.AreEqual(header.Odyssey, false);
         Assert.AreEqual(header.GameVersion, "3.5.3.400 EDH");
+        Assert.AreEqual(header.IsLegacy, true);
+        Assert.AreEqual(header.IsLive, false);
         // ~73k commits in two years. Not bad.
         Assert.AreEqual(header.Build, "r213094/r0 ");
     }