diff --git a/IRD/File.cs b/IRD/File.cs
index bc9e43d..4228325 100644
--- a/IRD/File.cs
+++ b/IRD/File.cs
@@ -7,7 +7,11 @@ namespace SabreTools.Models.IRD
         /// <summary>
         /// "3IRD"
         /// </summary>
+#if NET48
         public byte[] Magic { get; set; }
+#else
+        public byte[]? Magic { get; set; }
+#endif
 
         /// <summary>
         /// Version
@@ -19,7 +23,11 @@ namespace SabreTools.Models.IRD
         /// The same value stored in PARAM.SFO / TITLE_ID
         /// </summary>
         /// <remarks>9 bytes, ASCII, stored without dashes</remarks>
+#if NET48
         public string TitleID { get; set; }
+#else
+        public string? TitleID { get; set; }
+#endif
 
         /// <summary>
         /// Number of bytes that follow containing the title
@@ -30,25 +38,41 @@ namespace SabreTools.Models.IRD
         /// The same value stored in PARAM.SFO / TITLE
         /// </summary>
         /// <remarks><see cref="TitleLength"/> bytes, ASCII</remarks>
+#if NET48
         public string Title { get; set; }
+#else
+        public string? Title { get; set; }
+#endif
 
         /// <summary>
         /// The same value stored in PARAM.SFO / PS3_SYSTEM_VER
         /// </summary>
         /// <remarks>4 bytes, ASCII, missing uses "0000"</remarks>
+#if NET48
         public string SystemVersion { get; set; }
+#else
+        public string? SystemVersion { get; set; }
+#endif
 
         /// <summary>
         /// The same value stored in PARAM.SFO / VERSION
         /// </summary>
         /// <remarks>5 bytes, ASCII</remarks>
+#if NET48
         public string GameVersion { get; set; }
+#else
+        public string? GameVersion { get; set; }
+#endif
 
         /// <summary>
         /// The same value stored in PARAM.SFO / APP_VER
         /// </summary>
         /// <remarks>5 bytes, ASCII</remarks>
+#if NET48
         public string AppVersion { get; set; }
+#else
+        public string? AppVersion { get; set; }
+#endif
 
         /// <summary>
         /// Length of the gzip-compressed header data
@@ -58,7 +82,11 @@ namespace SabreTools.Models.IRD
         /// <summary>
         /// Gzip-compressed header data
         /// </summary>
+#if NET48
         public byte[] Header { get; set; }
+#else
+        public byte[]? Header { get; set; }
+#endif
 
         /// <summary>
         /// Length of the gzip-compressed footer data
@@ -68,7 +96,11 @@ namespace SabreTools.Models.IRD
         /// <summary>
         /// Gzip-compressed footer data
         /// </summary>
+#if NET48
         public byte[] Footer { get; set; }
+#else
+        public byte[]? Footer { get; set; }
+#endif
 
         /// <summary>
         /// Number of complete regions in the image
@@ -78,8 +110,12 @@ namespace SabreTools.Models.IRD
         /// <summary>
         /// MD5 hashes for all complete regions in the image
         /// </summary>
-        /// <remarks><see cref="RegionCount"/> regions, 16-bytes per hash</remarks> 
+        /// <remarks><see cref="RegionCount"/> regions, 16-bytes per hash</remarks>
+#if NET48
         public byte[][] RegionHashes { get; set; }
+#else
+        public byte[][]? RegionHashes { get; set; }
+#endif
 
         /// <summary>
         /// Number of decrypted files in the image
@@ -89,14 +125,22 @@ namespace SabreTools.Models.IRD
         /// <summary>
         /// Starting sector for each decrypted file
         /// </summary>
-        /// <remarks><see cref="FileCount"/> files, alternating with each <see cref="FileHashes"/> entry</remarks> 
+        /// <remarks><see cref="FileCount"/> files, alternating with each <see cref="FileHashes"/> entry</remarks>
+#if NET48
         public ulong[] FileKeys { get; set; }
+#else
+        public ulong[]? FileKeys { get; set; }
+#endif
 
         /// <summary>
         /// MD5 hashes for all decrypted files in the image
         /// </summary>
-        /// <remarks><see cref="FileCount"/> files, 16-bytes per hash, alternating with each <see cref="FileHashes"/> entry</remarks> 
+        /// <remarks><see cref="FileCount"/> files, 16-bytes per hash, alternating with each <see cref="FileHashes"/> entry</remarks>
+#if NET48
         public byte[][] FileHashes { get; set; }
+#else
+        public byte[][]? FileHashes { get; set; }
+#endif
 
         /// <summary>
         /// Extra Config, usually 0x0000
@@ -112,19 +156,31 @@ namespace SabreTools.Models.IRD
         /// D1 key
         /// </summary>
         /// <remarks>16 bytes</remarks>
+#if NET48
         public byte[] Data1Key { get; set; }
+#else
+        public byte[]? Data1Key { get; set; }
+#endif
 
         /// <summary>
         /// D2 key
         /// </summary>
         /// <remarks>16 bytes</remarks>
+#if NET48
         public byte[] Data2Key { get; set; }
+#else
+        public byte[]? Data2Key { get; set; }
+#endif
 
         /// <summary>
         /// Uncompressed PIC data
         /// </summary>
         /// <remarks>115 bytes, before D1/D2 keys on version 9</remarks>
+#if NET48
         public byte[] PIC { get; set; }
+#else
+        public byte[]? PIC { get; set; }
+#endif
 
         /// <summary>
         /// Unique Identifier