diff --git a/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs b/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
index b797393b..feab452a 100644
--- a/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
+++ b/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
@@ -3,7 +3,6 @@ using System.Diagnostics.CodeAnalysis;
 using Newtonsoft.Json;
 using NUnit.Framework;
 using StardewModdingAPI.Framework;
-using StardewModdingAPI.Toolkit.Serialisation.Models;
 
 namespace StardewModdingAPI.Tests.Utilities
 {
@@ -272,22 +271,6 @@ namespace StardewModdingAPI.Tests.Utilities
             Assert.IsTrue(version.IsOlderThan(new SemanticVersion("1.2.30")), "The game version should be considered older than the later semantic versions.");
         }
 
-        /****
-        ** LegacyManifestVersion
-        ****/
-        [Test(Description = "Assert that the LegacyManifestVersion subclass correctly parses legacy manifest versions.")]
-        [TestCase(1, 0, 0, null, ExpectedResult = "1.0")]
-        [TestCase(3000, 4000, 5000, null, ExpectedResult = "3000.4000.5000")]
-        [TestCase(1, 2, 3, "", ExpectedResult = "1.2.3")]
-        [TestCase(1, 2, 3, "    ", ExpectedResult = "1.2.3")]
-        [TestCase(1, 2, 3, "0", ExpectedResult = "1.2.3")]  // special case: drop '0' tag for legacy manifest versions
-        [TestCase(1, 2, 3, "some-tag.4", ExpectedResult = "1.2.3-some-tag.4")]
-        [TestCase(1, 2, 3, "some-tag.4   ", ExpectedResult = "1.2.3-some-tag.4")]
-        public string LegacyManifestVersion(int major, int minor, int patch, string tag)
-        {
-            return new LegacyManifestVersion(major, minor, patch, tag).ToString();
-        }
-
 
         /*********
         ** Private methods
diff --git a/src/SMAPI/Framework/Models/ManifestContentPackFor.cs b/src/SMAPI/Framework/Models/ManifestContentPackFor.cs
index cdad8893..90e20c6a 100644
--- a/src/SMAPI/Framework/Models/ManifestContentPackFor.cs
+++ b/src/SMAPI/Framework/Models/ManifestContentPackFor.cs
@@ -21,7 +21,7 @@ namespace StardewModdingAPI.Framework.Models
         public ManifestContentPackFor(Toolkit.Serialisation.Models.ManifestContentPackFor contentPackFor)
         {
             this.UniqueID = contentPackFor.UniqueID;
-            this.MinimumVersion = new SemanticVersion(contentPackFor.MinimumVersion);
+            this.MinimumVersion = contentPackFor.MinimumVersion != null ? new SemanticVersion(contentPackFor.MinimumVersion) : null;
         }
 
         /// <summary>Construct an instance.</summary>
diff --git a/src/SMAPI/Framework/Serialisation/SemanticVersionConverter.cs b/src/SMAPI/Framework/Serialisation/SemanticVersionConverter.cs
new file mode 100644
index 00000000..3e05a440
--- /dev/null
+++ b/src/SMAPI/Framework/Serialisation/SemanticVersionConverter.cs
@@ -0,0 +1,40 @@
+using Newtonsoft.Json.Linq;
+using StardewModdingAPI.Toolkit.Serialisation;
+using StardewModdingAPI.Toolkit.Serialisation.Converters;
+
+namespace StardewModdingAPI.Framework.Serialisation
+{
+    /// <summary>Handles deserialisation of <see cref="ISemanticVersion"/>.</summary>
+    internal class SemanticVersionConverter : SimpleReadOnlyConverter<ISemanticVersion>
+    {
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Read a JSON object.</summary>
+        /// <param name="obj">The JSON object to read.</param>
+        /// <param name="path">The path to the current JSON node.</param>
+        protected override ISemanticVersion ReadObject(JObject obj, string path)
+        {
+            int major = obj.ValueIgnoreCase<int>("MajorVersion");
+            int minor = obj.ValueIgnoreCase<int>("MinorVersion");
+            int patch = obj.ValueIgnoreCase<int>("PatchVersion");
+            string build = obj.ValueIgnoreCase<string>("Build");
+            if (build == "0")
+                build = null; // '0' from incorrect examples in old SMAPI documentation
+
+            return new SemanticVersion(major, minor, patch, build);
+        }
+
+        /// <summary>Read a JSON string.</summary>
+        /// <param name="str">The JSON string value.</param>
+        /// <param name="path">The path to the current JSON node.</param>
+        protected override ISemanticVersion ReadString(string str, string path)
+        {
+            if (string.IsNullOrWhiteSpace(str))
+                return null;
+            if (!SemanticVersion.TryParse(str, out ISemanticVersion version))
+                throw new SParseException($"Can't parse semantic version from invalid value '{str}', should be formatted like 1.2, 1.2.30, or 1.2.30-beta (path: {path}).");
+            return version;
+        }
+    }
+}
diff --git a/src/SMAPI/Program.cs b/src/SMAPI/Program.cs
index 05a3134e..cc59c0cd 100644
--- a/src/SMAPI/Program.cs
+++ b/src/SMAPI/Program.cs
@@ -159,7 +159,8 @@ namespace StardewModdingAPI
                 new StringEnumConverter<SButton>(),
                 new ColorConverter(),
                 new PointConverter(),
-                new RectangleConverter()
+                new RectangleConverter(),
+                new Framework.Serialisation.SemanticVersionConverter()
             };
             foreach (JsonConverter converter in converters)
                 this.JsonHelper.JsonSettings.Converters.Add(converter);
diff --git a/src/SMAPI/StardewModdingAPI.csproj b/src/SMAPI/StardewModdingAPI.csproj
index 3c953ec5..7eb5f95a 100644
--- a/src/SMAPI/StardewModdingAPI.csproj
+++ b/src/SMAPI/StardewModdingAPI.csproj
@@ -121,6 +121,7 @@
     <Compile Include="Framework\Models\ManifestContentPackFor.cs" />
     <Compile Include="Framework\Models\ManifestDependency.cs" />
     <Compile Include="Framework\ModHelpers\InputHelper.cs" />
+    <Compile Include="Framework\Serialisation\SemanticVersionConverter.cs" />
     <Compile Include="IInputHelper.cs" />
     <Compile Include="Framework\Input\SInputState.cs" />
     <Compile Include="Framework\Input\InputStatus.cs" />
diff --git a/src/StardewModdingAPI.Toolkit/Serialisation/Converters/SemanticVersionConverter.cs b/src/StardewModdingAPI.Toolkit/Serialisation/Converters/SemanticVersionConverter.cs
index 2075d27e..2ddaa1bf 100644
--- a/src/StardewModdingAPI.Toolkit/Serialisation/Converters/SemanticVersionConverter.cs
+++ b/src/StardewModdingAPI.Toolkit/Serialisation/Converters/SemanticVersionConverter.cs
@@ -18,7 +18,10 @@ namespace StardewModdingAPI.Toolkit.Serialisation.Converters
             int minor = obj.ValueIgnoreCase<int>("MinorVersion");
             int patch = obj.ValueIgnoreCase<int>("PatchVersion");
             string build = obj.ValueIgnoreCase<string>("Build");
-            return new LegacyManifestVersion(major, minor, patch, build);
+            if (build == "0")
+                build = null; // '0' from incorrect examples in old SMAPI documentation
+
+            return new SemanticVersion(major, minor, patch, build);
         }
 
         /// <summary>Read a JSON string.</summary>
diff --git a/src/StardewModdingAPI.Toolkit/Serialisation/Models/LegacyManifestVersion.cs b/src/StardewModdingAPI.Toolkit/Serialisation/Models/LegacyManifestVersion.cs
deleted file mode 100644
index 12f6755b..00000000
--- a/src/StardewModdingAPI.Toolkit/Serialisation/Models/LegacyManifestVersion.cs
+++ /dev/null
@@ -1,26 +0,0 @@
-using Newtonsoft.Json;
-
-namespace StardewModdingAPI.Toolkit.Serialisation.Models
-{
-    /// <summary>An implementation of <see cref="ISemanticVersion"/> that hamdles the legacy <see cref="Manifest"/> version format.</summary>
-    public class LegacyManifestVersion : SemanticVersion
-    {
-        /*********
-        ** Public methods
-        *********/
-        /// <summary>Construct an instance.</summary>
-        /// <param name="majorVersion">The major version incremented for major API changes.</param>
-        /// <param name="minorVersion">The minor version incremented for backwards-compatible changes.</param>
-        /// <param name="patchVersion">The patch version for backwards-compatible bug fixes.</param>
-        /// <param name="build">An optional build tag.</param>
-        [JsonConstructor]
-        public LegacyManifestVersion(int majorVersion, int minorVersion, int patchVersion, string build = null)
-            : base(
-                majorVersion,
-                minorVersion,
-                patchVersion,
-                build != "0" ? build : null // '0' from incorrect examples in old SMAPI documentation
-            )
-        { }
-    }
-}