diff --git a/SabreTools.DatFiles/DatFile.cs b/SabreTools.DatFiles/DatFile.cs
index f4e6f2ad..56375711 100644
--- a/SabreTools.DatFiles/DatFile.cs
+++ b/SabreTools.DatFiles/DatFile.cs
@@ -115,7 +115,7 @@ namespace SabreTools.DatFiles
         /// <param name="datHeader">DatHeader to get the values from</param>
         public static DatFile Create(DatHeader datHeader)
         {
-            DatFile datFile = Create(datHeader.DatFormat);
+            DatFile datFile = Create(datHeader.GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             datFile.Header = (DatHeader)datHeader.Clone();
             return datFile;
         }
@@ -636,7 +636,7 @@ namespace SabreTools.DatFiles
             if (!GetSupportedTypes().Contains(datItem.GetFieldValue<ItemType>(Models.Metadata.DatItem.TypeKey)))
             {
                 string itemString = JsonConvert.SerializeObject(datItem, Formatting.None);
-                logger?.Verbose($"Item '{itemString}' was skipped because it was not supported in {Header?.DatFormat}");
+                logger?.Verbose($"Item '{itemString}' was skipped because it was not supported in {Header?.GetFieldValue<DatFormat>(DatHeader.DatFormatKey)}");
                 return true;
             }
 
@@ -646,9 +646,9 @@ namespace SabreTools.DatFiles
             {
                 string itemString = JsonConvert.SerializeObject(datItem, Formatting.None);
 #if NET20 || NET35
-                logger?.Verbose($"Item '{itemString}' was skipped because it was missing required fields for {Header?.DatFormat}: {string.Join(", ", [.. missingFields])}");
+                logger?.Verbose($"Item '{itemString}' was skipped because it was missing required fields for {Header?.GetFieldValue<DatFormat>(DatHeader.DatFormatKey)}: {string.Join(", ", [.. missingFields])}");
 #else
-                logger?.Verbose($"Item '{itemString}' was skipped because it was missing required fields for {Header?.DatFormat}: {string.Join(", ", missingFields)}");
+                logger?.Verbose($"Item '{itemString}' was skipped because it was missing required fields for {Header?.GetFieldValue<DatFormat>(DatHeader.DatFormatKey)}: {string.Join(", ", missingFields)}");
 #endif
                 return true;
             }
diff --git a/SabreTools.DatFiles/DatHeader.cs b/SabreTools.DatFiles/DatHeader.cs
index 05648dd5..8e1d4ac9 100644
--- a/SabreTools.DatFiles/DatHeader.cs
+++ b/SabreTools.DatFiles/DatHeader.cs
@@ -23,6 +23,11 @@ namespace SabreTools.DatFiles
         /// </summary>
         public const string AddExtensionKey = "ADDEXTENSION";
 
+        /// <summary>
+        /// Read or write format
+        /// </summary>
+        public const string DatFormatKey = "DATFORMAT";
+
         /// <summary>
         /// External name of the DAT
         /// </summary>
@@ -67,12 +72,6 @@ namespace SabreTools.DatFiles
 
         #region Fields
 
-        /// <summary>
-        /// Read or write format
-        /// </summary>
-        [JsonIgnore, XmlIgnore]
-        public DatFormat DatFormat { get; set; }
-
         [JsonIgnore]
         public bool InfosSpecified
         {
@@ -166,11 +165,10 @@ namespace SabreTools.DatFiles
         {
             var header = new DatHeader()
             {
-                DatFormat = this.DatFormat,
-
                 InputDepot = this.InputDepot?.Clone() as DepotInformation,
                 OutputDepot = this.OutputDepot?.Clone() as DepotInformation,
             };
+            header.SetFieldValue<string?>(DatHeader.AddExtensionKey, GetFieldValue<string?>(DatHeader.AddExtensionKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.AuthorKey, GetFieldValue<string?>(Models.Metadata.Header.AuthorKey));
             header.SetFieldValue<MergingFlag>(Models.Metadata.Header.BiosModeKey, GetFieldValue<MergingFlag>(Models.Metadata.Header.BiosModeKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.BuildKey, GetFieldValue<string?>(Models.Metadata.Header.BuildKey));
@@ -178,6 +176,7 @@ namespace SabreTools.DatFiles
             header.SetFieldValue<string?>(Models.Metadata.Header.CategoryKey, GetFieldValue<string?>(Models.Metadata.Header.CategoryKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.CommentKey, GetFieldValue<string?>(Models.Metadata.Header.CommentKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.DateKey, GetFieldValue<string?>(Models.Metadata.Header.DateKey));
+            header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.DatVersionKey, GetFieldValue<string?>(Models.Metadata.Header.DatVersionKey));
             header.SetFieldValue<bool?>(Models.Metadata.Header.DebugKey, GetFieldValue<bool?>(Models.Metadata.Header.DebugKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.DescriptionKey, GetFieldValue<string?>(Models.Metadata.Header.DescriptionKey));
@@ -186,6 +185,7 @@ namespace SabreTools.DatFiles
             header.SetFieldValue<MergingFlag>(Models.Metadata.Header.ForceMergingKey, GetFieldValue<MergingFlag>(Models.Metadata.Header.ForceMergingKey));
             header.SetFieldValue<NodumpFlag>(Models.Metadata.Header.ForceNodumpKey, GetFieldValue<NodumpFlag>(Models.Metadata.Header.ForceNodumpKey));
             header.SetFieldValue<PackingFlag>(Models.Metadata.Header.ForcePackingKey, GetFieldValue<PackingFlag>(Models.Metadata.Header.ForcePackingKey));
+            header.SetFieldValue<bool>(DatHeader.GameNameKey, GetFieldValue<bool>(DatHeader.GameNameKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.HeaderKey, GetFieldValue<string?>(Models.Metadata.Header.HeaderKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.HomepageKey, GetFieldValue<string?>(Models.Metadata.Header.HomepageKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.IdKey, GetFieldValue<string?>(Models.Metadata.Header.IdKey));
@@ -195,6 +195,11 @@ namespace SabreTools.DatFiles
             header.SetFieldValue<bool?>(Models.Metadata.Header.LockSampleModeKey, GetFieldValue<bool?>(Models.Metadata.Header.LockSampleModeKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.MameConfigKey, GetFieldValue<string?>(Models.Metadata.Header.MameConfigKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.NameKey, GetFieldValue<string?>(Models.Metadata.Header.NameKey));
+            header.SetFieldValue<string?>(DatHeader.PostfixKey, GetFieldValue<string?>(DatHeader.PostfixKey));
+            header.SetFieldValue<string?>(DatHeader.PrefixKey, GetFieldValue<string?>(DatHeader.PrefixKey));
+            header.SetFieldValue<bool>(DatHeader.QuotesKey, GetFieldValue<bool>(DatHeader.QuotesKey));
+            header.SetFieldValue<bool>(DatHeader.RemoveExtensionKey, GetFieldValue<bool>(DatHeader.RemoveExtensionKey));
+            header.SetFieldValue<string?>(DatHeader.ReplaceExtensionKey, GetFieldValue<string?>(DatHeader.ReplaceExtensionKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.RomTitleKey, GetFieldValue<string?>(Models.Metadata.Header.RomTitleKey));
             header.SetFieldValue<MergingFlag>(Models.Metadata.Header.RomModeKey, GetFieldValue<MergingFlag>(Models.Metadata.Header.RomModeKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.RootDirKey, GetFieldValue<string?>(Models.Metadata.Header.RootDirKey));
@@ -204,16 +209,8 @@ namespace SabreTools.DatFiles
             header.SetFieldValue<string?>(Models.Metadata.Header.SystemKey, GetFieldValue<string?>(Models.Metadata.Header.SystemKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.TypeKey, GetFieldValue<string?>(Models.Metadata.Header.TypeKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.UrlKey, GetFieldValue<string?>(Models.Metadata.Header.UrlKey));
-            header.SetFieldValue<string?>(Models.Metadata.Header.VersionKey, GetFieldValue<string?>(Models.Metadata.Header.VersionKey));
-
-            header.SetFieldValue<string?>(DatHeader.AddExtensionKey, GetFieldValue<string?>(DatHeader.AddExtensionKey));
-            header.SetFieldValue<bool>(DatHeader.GameNameKey, GetFieldValue<bool>(DatHeader.GameNameKey));
-            header.SetFieldValue<string?>(DatHeader.PostfixKey, GetFieldValue<string?>(DatHeader.PostfixKey));
-            header.SetFieldValue<string?>(DatHeader.PrefixKey, GetFieldValue<string?>(DatHeader.PrefixKey));
-            header.SetFieldValue<bool>(DatHeader.RemoveExtensionKey, GetFieldValue<bool>(DatHeader.RemoveExtensionKey));
-            header.SetFieldValue<string?>(DatHeader.ReplaceExtensionKey, GetFieldValue<string?>(DatHeader.ReplaceExtensionKey));
-            header.SetFieldValue<bool>(DatHeader.QuotesKey, GetFieldValue<bool>(DatHeader.QuotesKey));
             header.SetFieldValue<bool>(DatHeader.UseRomNameKey, GetFieldValue<bool>(DatHeader.UseRomNameKey));
+            header.SetFieldValue<string?>(Models.Metadata.Header.VersionKey, GetFieldValue<string?>(Models.Metadata.Header.VersionKey));
 
             return header;
         }
@@ -223,14 +220,12 @@ namespace SabreTools.DatFiles
         /// </summary>
         public DatHeader CloneStandard()
         {
-            var header = new DatHeader()
-            {
-                DatFormat = this.DatFormat,
-            };
+            var header = new DatHeader();
             header.SetFieldValue<string?>(Models.Metadata.Header.AuthorKey, GetFieldValue<string?>(Models.Metadata.Header.AuthorKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.CategoryKey, GetFieldValue<string?>(Models.Metadata.Header.CategoryKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.CommentKey, GetFieldValue<string?>(Models.Metadata.Header.CommentKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.DateKey, GetFieldValue<string?>(Models.Metadata.Header.DateKey));
+            header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.DescriptionKey, GetFieldValue<string?>(Models.Metadata.Header.DescriptionKey));
             header.SetFieldValue<string?>(Models.Metadata.Header.EmailKey, GetFieldValue<string?>(Models.Metadata.Header.EmailKey));
             header.SetFieldValue<string?>(DatHeader.FileNameKey, GetFieldValue<string?>(DatHeader.FileNameKey));
@@ -255,12 +250,11 @@ namespace SabreTools.DatFiles
         {
             var header = new DatHeader()
             {
-                DatFormat = this.DatFormat,
-
                 InputDepot = this.InputDepot?.Clone() as DepotInformation,
                 OutputDepot = this.OutputDepot?.Clone() as DepotInformation,
             };
             header.SetFieldValue<string?>(DatHeader.AddExtensionKey, GetFieldValue<string?>(DatHeader.AddExtensionKey));
+            header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             header.SetFieldValue<bool>(DatHeader.GameNameKey, GetFieldValue<bool>(DatHeader.GameNameKey));
             header.SetFieldValue<string?>(DatHeader.PostfixKey, GetFieldValue<string?>(DatHeader.PostfixKey));
             header.SetFieldValue<string?>(DatHeader.PrefixKey, GetFieldValue<string?>(DatHeader.PrefixKey));
@@ -332,8 +326,8 @@ namespace SabreTools.DatFiles
             if (datHeader.GetFieldValue<PackingFlag>(Models.Metadata.Header.ForcePackingKey) != PackingFlag.None)
                 SetFieldValue<PackingFlag>(Models.Metadata.Header.ForcePackingKey, datHeader.GetFieldValue<PackingFlag>(Models.Metadata.Header.ForcePackingKey));
 
-            if (datHeader.DatFormat != 0x00)
-                DatFormat = datHeader.DatFormat;
+            if (datHeader.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) != 0x00)
+                SetFieldValue<DatFormat>(DatHeader.DatFormatKey, datHeader.GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
 
             if (!string.IsNullOrEmpty(datHeader.GetFieldValue<string?>(DatHeader.PrefixKey)))
                 SetFieldValue<string?>(DatHeader.PrefixKey, datHeader.GetFieldValue<string?>(DatHeader.PrefixKey));
@@ -421,9 +415,9 @@ namespace SabreTools.DatFiles
 
             // CSV
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.CSV) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.CSV) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.CSV))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.CSV))
 #endif
             {
                 outfileNames.Add(DatFormat.CSV, CreateOutFileNamesHelper(outDir, ".csv", overwrite));
@@ -436,9 +430,9 @@ namespace SabreTools.DatFiles
 
             // ClrMamePro
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.ClrMamePro) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.ClrMamePro) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.ClrMamePro))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.ClrMamePro))
 #endif
             {
                 outfileNames.Add(DatFormat.ClrMamePro, CreateOutFileNamesHelper(outDir, ".dat", overwrite));
@@ -447,9 +441,9 @@ namespace SabreTools.DatFiles
 
             // RomCenter
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RomCenter) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RomCenter) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RomCenter))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RomCenter))
 #endif
             {
                 if (usedExtensions.Contains(".dat"))
@@ -466,9 +460,9 @@ namespace SabreTools.DatFiles
 
             // DOSCenter
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.DOSCenter) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.DOSCenter) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.DOSCenter))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.DOSCenter))
 #endif
             {
                 if (usedExtensions.Contains(".dat"))
@@ -489,9 +483,9 @@ namespace SabreTools.DatFiles
 
             // JSON
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.SabreJSON) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.SabreJSON) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.SabreJSON))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.SabreJSON))
 #endif
             {
                 outfileNames.Add(DatFormat.SabreJSON, CreateOutFileNamesHelper(outDir, ".json", overwrite));
@@ -504,9 +498,9 @@ namespace SabreTools.DatFiles
 
             // Redump MD5
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpMD5) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpMD5) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpMD5))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpMD5))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpMD5, CreateOutFileNamesHelper(outDir, ".md5", overwrite));
@@ -519,9 +513,9 @@ namespace SabreTools.DatFiles
 
             // Redump SFV
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSFV) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSFV) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSFV))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSFV))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSFV, CreateOutFileNamesHelper(outDir, ".sfv", overwrite));
@@ -534,9 +528,9 @@ namespace SabreTools.DatFiles
 
             // Redump SHA-1
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSHA1) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSHA1) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSHA1))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSHA1))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSHA1, CreateOutFileNamesHelper(outDir, ".sha1", overwrite));
@@ -549,9 +543,9 @@ namespace SabreTools.DatFiles
 
             // Redump SHA-256
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSHA256) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSHA256) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSHA256))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSHA256))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSHA256, CreateOutFileNamesHelper(outDir, ".sha256", overwrite));
@@ -564,9 +558,9 @@ namespace SabreTools.DatFiles
 
             // Redump SHA-384
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSHA384) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSHA384) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSHA384))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSHA384))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSHA384, CreateOutFileNamesHelper(outDir, ".sha384", overwrite));
@@ -579,9 +573,9 @@ namespace SabreTools.DatFiles
 
             // Redump SHA-512
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSHA512) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSHA512) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSHA512))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSHA512))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSHA512, CreateOutFileNamesHelper(outDir, ".sha512", overwrite));
@@ -594,9 +588,9 @@ namespace SabreTools.DatFiles
 
             // Redump SpamSum
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.RedumpSpamSum) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.RedumpSpamSum) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.RedumpSpamSum))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.RedumpSpamSum))
 #endif
             {
                 outfileNames.Add(DatFormat.RedumpSpamSum, CreateOutFileNamesHelper(outDir, ".spamsum", overwrite));
@@ -609,9 +603,9 @@ namespace SabreTools.DatFiles
 
             // SSV
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.SSV) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.SSV) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.SSV))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.SSV))
 #endif
             {
                 outfileNames.Add(DatFormat.SSV, CreateOutFileNamesHelper(outDir, ".ssv", overwrite));
@@ -624,9 +618,9 @@ namespace SabreTools.DatFiles
 
             // TSV
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.TSV) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.TSV) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.TSV))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.TSV))
 #endif
             {
                 outfileNames.Add(DatFormat.TSV, CreateOutFileNamesHelper(outDir, ".tsv", overwrite));
@@ -639,9 +633,9 @@ namespace SabreTools.DatFiles
 
             // AttractMode
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.AttractMode) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.AttractMode) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.AttractMode))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.AttractMode))
 #endif
             {
                 outfileNames.Add(DatFormat.AttractMode, CreateOutFileNamesHelper(outDir, ".txt", overwrite));
@@ -650,9 +644,9 @@ namespace SabreTools.DatFiles
 
             // MAME Listroms
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.Listrom) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.Listrom) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.Listrom))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.Listrom))
 #endif
             {
                 if (usedExtensions.Contains(".txt"))
@@ -669,9 +663,9 @@ namespace SabreTools.DatFiles
 
             // Missfile
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.MissFile) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.MissFile) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.MissFile))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.MissFile))
 #endif
             {
                 if (usedExtensions.Contains(".txt"))
@@ -688,9 +682,9 @@ namespace SabreTools.DatFiles
 
             // Everdrive SMDB
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.EverdriveSMDB) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.EverdriveSMDB) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.EverdriveSMDB))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.EverdriveSMDB))
 #endif
             {
                 if (usedExtensions.Contains(".txt"))
@@ -711,18 +705,18 @@ namespace SabreTools.DatFiles
 
             // Logiqx XML
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.Logiqx) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.Logiqx) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.Logiqx))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.Logiqx))
 #endif
             {
                 outfileNames.Add(DatFormat.Logiqx, CreateOutFileNamesHelper(outDir, ".xml", overwrite));
                 usedExtensions.Add(".xml");
             }
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.LogiqxDeprecated) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.LogiqxDeprecated) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.LogiqxDeprecated))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.LogiqxDeprecated))
 #endif
             {
                 outfileNames.Add(DatFormat.LogiqxDeprecated, CreateOutFileNamesHelper(outDir, ".xml", overwrite));
@@ -731,9 +725,9 @@ namespace SabreTools.DatFiles
 
             // SabreDAT
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.SabreXML) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.SabreXML) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.SabreXML))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.SabreXML))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
@@ -750,9 +744,9 @@ namespace SabreTools.DatFiles
 
             // Software List
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.SoftwareList) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.SoftwareList) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.SoftwareList))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.SoftwareList))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
@@ -769,9 +763,9 @@ namespace SabreTools.DatFiles
 
             // MAME Listxml
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.Listxml) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.Listxml) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.Listxml))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.Listxml))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
@@ -788,9 +782,9 @@ namespace SabreTools.DatFiles
 
             // OfflineList
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.OfflineList) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.OfflineList) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.OfflineList))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.OfflineList))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
@@ -807,9 +801,9 @@ namespace SabreTools.DatFiles
 
             // openMSX
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.OpenMSX) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.OpenMSX) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.OpenMSX))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.OpenMSX))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
@@ -826,9 +820,9 @@ namespace SabreTools.DatFiles
 
             // Archive.org
 #if NETFRAMEWORK
-            if ((DatFormat & DatFormat.ArchiveDotOrg) != 0)
+            if ((GetFieldValue<DatFormat>(DatHeader.DatFormatKey) & DatFormat.ArchiveDotOrg) != 0)
 #else
-            if (DatFormat.HasFlag(DatFormat.ArchiveDotOrg))
+            if (GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.ArchiveDotOrg))
 #endif
             {
                 if (usedExtensions.Contains(".xml"))
diff --git a/SabreTools.DatTools/Parser.cs b/SabreTools.DatTools/Parser.cs
index 44a64bbc..0e53ea84 100644
--- a/SabreTools.DatTools/Parser.cs
+++ b/SabreTools.DatTools/Parser.cs
@@ -102,7 +102,9 @@ namespace SabreTools.DatTools
 
             // If the output type isn't set already, get the internal output type
             DatFormat currentPathFormat = GetDatFormat(currentPath);
-            datFile.Header.DatFormat = datFile.Header.DatFormat == 0 ? currentPathFormat : datFile.Header.DatFormat;
+            datFile.Header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) == 0
+                ? currentPathFormat
+                : datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             datFile.Items.SetBucketedBy(ItemKey.CRC); // Setting this because it can reduce issues later
 
             InternalStopwatch watch = new($"Parsing '{currentPath}' into internal DAT");
diff --git a/SabreTools.DatTools/Writer.cs b/SabreTools.DatTools/Writer.cs
index ff161b36..3fa5c837 100644
--- a/SabreTools.DatTools/Writer.cs
+++ b/SabreTools.DatTools/Writer.cs
@@ -58,10 +58,10 @@ namespace SabreTools.DatTools
             InternalStopwatch watch = new($"Writing out internal dat to '{outDir}'");
 
             // If the DAT has no output format, default to XML
-            if (datFile.Header.DatFormat == 0)
+            if (datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) == 0)
             {
                 logger.Verbose("No DAT format defined, defaulting to XML");
-                datFile.Header.DatFormat = DatFormat.Logiqx;
+                datFile.Header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, DatFormat.Logiqx);
             }
 
             // Make sure that the three essential fields are filled in
diff --git a/SabreTools.Test/DatFiles/DatHeaderTests.cs b/SabreTools.Test/DatFiles/DatHeaderTests.cs
index 296befba..e87ed93f 100644
--- a/SabreTools.Test/DatFiles/DatHeaderTests.cs
+++ b/SabreTools.Test/DatFiles/DatHeaderTests.cs
@@ -14,11 +14,9 @@ namespace SabreTools.Test.DatFiles
         public void CreateOutFileNamesTest(DatFormat datFormat, string extension)
         {
             // Create the empty DatHeader
-            var datHeader = new DatHeader
-            {
-                DatFormat = datFormat,
-            };
+            var datHeader = new DatHeader();
             datHeader.SetFieldValue<string?>(DatHeader.FileNameKey, "test.dat");
+            datHeader.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, datFormat);
 
             // Invoke the method
             string outDir = "C:\\Test";
@@ -34,11 +32,9 @@ namespace SabreTools.Test.DatFiles
         public void CreateOutFileNamesAllOutputsTest()
         {
             // Create the empty DatHeader
-            var datHeader = new DatHeader
-            {
-                DatFormat = DatFormat.ALL,
-            };
+            var datHeader = new DatHeader();
             datHeader.SetFieldValue<string?>(DatHeader.FileNameKey, "test.dat");
+            datHeader.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, DatFormat.ALL);
 
             // Invoke the method
             string outDir = "C:\\Test";
diff --git a/SabreTools.Test/DatTools/ParserTests.cs b/SabreTools.Test/DatTools/ParserTests.cs
index 26967a98..d441d5d7 100644
--- a/SabreTools.Test/DatTools/ParserTests.cs
+++ b/SabreTools.Test/DatTools/ParserTests.cs
@@ -42,7 +42,7 @@ namespace SabreTools.Test.DatTools
                 filename = Path.Combine(Environment.CurrentDirectory, "TestData", filename);
         
             var datFile = SabreTools.DatTools.Parser.CreateAndParse(filename, throwOnError: true);
-            Assert.Equal(datFormat, datFile.Header.DatFormat);
+            Assert.Equal(datFormat, datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey));
             Assert.Equal(totalCount, datFile.Items.TotalCount);
         }
     }
diff --git a/SabreTools/Features/BaseFeature.cs b/SabreTools/Features/BaseFeature.cs
index 95022666..d7f3bf9d 100644
--- a/SabreTools/Features/BaseFeature.cs
+++ b/SabreTools/Features/BaseFeature.cs
@@ -2198,11 +2198,11 @@ Some special strings that can be used:
                 }
                 else if (dftemp == DatFormat.Logiqx && deprecated)
                 {
-                    datHeader.DatFormat |= DatFormat.LogiqxDeprecated;
+                    datHeader.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, datHeader.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) | DatFormat.LogiqxDeprecated);
                 }
                 else
                 {
-                    datHeader.DatFormat |= dftemp;
+                    datHeader.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, datHeader.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) | dftemp);
                 }
             }
 
diff --git a/SabreTools/Features/Batch.cs b/SabreTools/Features/Batch.cs
index c025d7d2..680d0dfa 100644
--- a/SabreTools/Features/Batch.cs
+++ b/SabreTools/Features/Batch.cs
@@ -480,10 +480,10 @@ Reset the internal state:           reset();";
             public override void Process(BatchState batchState)
             {
                 // Assume there could be multiple
-                batchState.DatFile.Header.DatFormat = 0x00;
+                batchState.DatFile.Header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, 0x00);
                 foreach (string format in Arguments)
                 {
-                    batchState.DatFile.Header.DatFormat |= GetDatFormat(format);
+                    batchState.DatFile.Header.SetFieldValue<DatFormat>(DatHeader.DatFormatKey, batchState.DatFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey) | GetDatFormat(format));
                 }
             }
         }
@@ -804,7 +804,7 @@ Reset the internal state:           reset();";
 
                 // Read in the individual arguments
                 (string? type, string? key) = FilterParser.ParseFilterId(Arguments[0]);
-                
+
                 // If we had an invalid input, log and continue
                 if ((type == null || !string.Equals(type, Models.Metadata.MetadataFile.HeaderKey, StringComparison.OrdinalIgnoreCase)) && key == null)
                 {
diff --git a/SabreTools/Features/Update.cs b/SabreTools/Features/Update.cs
index 800b11b0..19ab16a1 100644
--- a/SabreTools/Features/Update.cs
+++ b/SabreTools/Features/Update.cs
@@ -167,9 +167,9 @@ namespace SabreTools.Features
                     DatFile datFile = DatFile.Create(Header);
                     logger.User($"Processing '{Path.GetFileName(inputPath.CurrentPath)}'");
                     Parser.ParseInto(datFile, inputPath, keep: true,
-                        keepext: datFile.Header.DatFormat.HasFlag(DatFormat.TSV)
-                            || datFile.Header.DatFormat.HasFlag(DatFormat.CSV)
-                            || datFile.Header.DatFormat.HasFlag(DatFormat.SSV));
+                        keepext: datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.TSV)
+                            || datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.CSV)
+                            || datFile.Header.GetFieldValue<DatFormat>(DatHeader.DatFormatKey).HasFlag(DatFormat.SSV));
 
                     // Perform additional processing steps
                     Extras!.ApplyExtras(datFile);