diff --git a/.github/actions/build-release/action.yml b/.github/actions/build-release/action.yml
index ba231d4..7b8e790 100644
--- a/.github/actions/build-release/action.yml
+++ b/.github/actions/build-release/action.yml
@@ -11,9 +11,7 @@ runs:
     - name: Setup dotnet build tools
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: |
-          6.0
-          7.0
+        dotnet-version: 8.0
 
     - name: Display dotnet version
       shell: bash
diff --git a/.github/actions/ci/action.yml b/.github/actions/ci/action.yml
index 8c2dc10..b0c6119 100644
--- a/.github/actions/ci/action.yml
+++ b/.github/actions/ci/action.yml
@@ -11,9 +11,7 @@ runs:
     - name: Setup dotnet build tools
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: |
-          6.0
-          7.0
+        dotnet-version: 8.0
 
     - run: dotnet --version
       shell: bash
diff --git a/.github/actions/full-release/action.yml b/.github/actions/full-release/action.yml
index c596ce6..8177c27 100644
--- a/.github/actions/full-release/action.yml
+++ b/.github/actions/full-release/action.yml
@@ -31,7 +31,7 @@ runs:
     - name: CI check
       uses: ./.github/actions/ci
       with:
-        framework_target: "net6.0"
+        framework_target: "net8.0"
 
     - uses: launchdarkly/gh-actions/actions/release-secrets@release-secrets-v1.2.0
       name: Get secrets
diff --git a/.github/actions/publish-package/action.yml b/.github/actions/publish-package/action.yml
index 37a8270..10cf8a7 100644
--- a/.github/actions/publish-package/action.yml
+++ b/.github/actions/publish-package/action.yml
@@ -13,9 +13,7 @@ runs:
     - name: Setup dotnet build tools
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: | 
-              6.0
-              7.0
+        dotnet-version: 8.0
 
     - name: Install Workloads
       shell: bash
diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index a2dcfa6..30c39eb 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -15,8 +15,7 @@ jobs:
     strategy:
       matrix:
         framework:
-          - { target: 'netcoreapp3.1', image: 'sdk:3.1-focal' }
-          - { target: 'net6.0', image: 'sdk:6.0-focal' }
+          - { target: 'net8.0', image: 'sdk:8.0' }
     runs-on: ubuntu-latest
     container: mcr.microsoft.com/dotnet/${{ matrix.framework.image }}
     env:
diff --git a/src/LaunchDarkly.InternalSdk/Http/HttpProperties.cs b/src/LaunchDarkly.InternalSdk/Http/HttpProperties.cs
index 7b043a6..c2e3ce7 100644
--- a/src/LaunchDarkly.InternalSdk/Http/HttpProperties.cs
+++ b/src/LaunchDarkly.InternalSdk/Http/HttpProperties.cs
@@ -267,7 +267,7 @@ public HttpMessageHandler NewHttpMessageHandler() =>
 
         private static HttpMessageHandler DefaultHttpMessageHandlerFactory(HttpProperties props)
         {
-#if NETCOREAPP || NET6_0
+#if NETCOREAPP
             return new SocketsHttpHandler
             {
                 ConnectTimeout = props.ConnectTimeout,
diff --git a/src/LaunchDarkly.InternalSdk/JsonConverterHelpers.cs b/src/LaunchDarkly.InternalSdk/JsonConverterHelpers.cs
index b8fea11..0004b1d 100644
--- a/src/LaunchDarkly.InternalSdk/JsonConverterHelpers.cs
+++ b/src/LaunchDarkly.InternalSdk/JsonConverterHelpers.cs
@@ -185,7 +185,7 @@ public static void WriteLdValueIfNotNull(Utf8JsonWriter w, string name, LdValue
         /// <param name="reader">the JSON reader</param>
         /// <returns>an <see cref="ArrayHelper"/></returns>
         /// <exception cref="JsonException">if the next token is not the beginning of an array</exception>
-        public static ArrayHelper RequireArray(ref Utf8JsonReader reader) =>
+        public static ArrayHelper RequireArray(scoped ref Utf8JsonReader reader) =>
             new ArrayHelper(ref reader, false);
 
         /// <summary>
@@ -195,7 +195,7 @@ public static ArrayHelper RequireArray(ref Utf8JsonReader reader) =>
         /// <param name="reader">the JSON reader</param>
         /// <returns>an <see cref="ArrayHelper"/></returns>
         /// <exception cref="JsonException">if the next token is not the beginning of an array or null</exception>
-        public static ArrayHelper RequireArrayOrNull(ref Utf8JsonReader reader) =>
+        public static ArrayHelper RequireArrayOrNull(scoped ref Utf8JsonReader reader) =>
             new ArrayHelper(ref reader, true);
 
         /// <summary>
@@ -205,7 +205,7 @@ public static ArrayHelper RequireArrayOrNull(ref Utf8JsonReader reader) =>
         /// <param name="reader">the JSON reader</param>
         /// <returns>an <see cref="ObjectHelper"/></returns>
         /// <exception cref="JsonException">if the next token is not the beginning of an object</exception>
-        public static ObjectHelper RequireObject(ref Utf8JsonReader reader)
+        public static ObjectHelper RequireObject(scoped ref Utf8JsonReader reader)
         {
             if (reader.TokenType == JsonTokenType.None)
             {
@@ -222,7 +222,7 @@ public static ObjectHelper RequireObject(ref Utf8JsonReader reader)
         /// <param name="reader">the JSON reader</param>
         /// <returns>an <see cref="ObjectHelper"/></returns>
         /// <exception cref="JsonException">if the next token is not the beginning of an object or null</exception>
-        public static ObjectHelper RequireObjectOrNull(ref Utf8JsonReader reader)
+        public static ObjectHelper RequireObjectOrNull(scoped ref Utf8JsonReader reader)
         {
             if (reader.TokenType == JsonTokenType.None)
             {
@@ -245,7 +245,7 @@ public ref struct ArrayHelper
         {
             private readonly bool _empty;
 
-            internal ArrayHelper(ref Utf8JsonReader reader, bool allowNull)
+            internal ArrayHelper(scoped ref Utf8JsonReader reader, bool allowNull)
             {
                 if (reader.TokenType == JsonTokenType.None)
                 {
@@ -268,7 +268,7 @@ internal ArrayHelper(ref Utf8JsonReader reader, bool allowNull)
             /// </summary>
             /// <param name="reader">the JSON reader (this must be passed again due to ref struct rules)</param>
             /// <returns>true if there is an element, false if this is the end</returns>
-            public bool Next(ref Utf8JsonReader reader) =>
+            public bool Next(scoped ref Utf8JsonReader reader) =>
                 !_empty && reader.Read() && reader.TokenType != JsonTokenType.EndArray;
         }
 
@@ -360,7 +360,7 @@ public ObjectHelper WithRequiredProperties(params string[] propertyNames) =>
             /// </summary>
             /// <param name="reader">the JSON reader (this must be passed again due to ref struct rules)</param>
             /// <returns>true if there is a property, false if this is the end</returns>
-            public bool Next(ref Utf8JsonReader reader)
+            public bool Next(scoped ref Utf8JsonReader reader)
             {
                 if (!_defined)
                 {
diff --git a/src/LaunchDarkly.InternalSdk/LaunchDarkly.InternalSdk.csproj b/src/LaunchDarkly.InternalSdk/LaunchDarkly.InternalSdk.csproj
index 5c96876..7ad34a9 100644
--- a/src/LaunchDarkly.InternalSdk/LaunchDarkly.InternalSdk.csproj
+++ b/src/LaunchDarkly.InternalSdk/LaunchDarkly.InternalSdk.csproj
@@ -8,12 +8,12 @@
       an environment variable is that we want to be able to run CI tests using .NET
       SDKs that may not support all of these target frameworks.
     -->
-    <BuildFrameworks Condition="'$(BUILDFRAMEWORKS)' == ''">netstandard2.0;netcoreapp3.1;net462;net6.0</BuildFrameworks>
+    <BuildFrameworks Condition="'$(BUILDFRAMEWORKS)' == ''">netstandard2.0;net462;net8.0</BuildFrameworks>
     <TargetFrameworks>$(BUILDFRAMEWORKS)</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>LaunchDarkly.InternalSdk</AssemblyName>
     <OutputType>Library</OutputType>
-    <LangVersion>7.3</LangVersion>
+    <LangVersion>11</LangVersion>
     <PackageId>LaunchDarkly.InternalSdk</PackageId>
     <RootNamespace>LaunchDarkly.Sdk.Internal</RootNamespace>
     <Description>LaunchDarkly internal common code for .NET and Xamarin clients</Description>
@@ -27,7 +27,7 @@
     <RepositoryBranch>main</RepositoryBranch>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'net462' or '$(TargetFramework)' == 'netcoreapp3.1'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'net462'">
     <PackageReference Include="System.Collections.Immutable" Version="1.7.1" />
   </ItemGroup>
 
diff --git a/test/LaunchDarkly.InternalSdk.Tests/JsonConverterHelpersTest.cs b/test/LaunchDarkly.InternalSdk.Tests/JsonConverterHelpersTest.cs
index 836c36d..3908d12 100644
--- a/test/LaunchDarkly.InternalSdk.Tests/JsonConverterHelpersTest.cs
+++ b/test/LaunchDarkly.InternalSdk.Tests/JsonConverterHelpersTest.cs
@@ -184,7 +184,7 @@ public void NonEmptyArray()
             VerifyNonEmptyArray(ref r2, ref a2);
         }
 
-        private void VerifyNonEmptyArray(ref Utf8JsonReader r, ref ArrayHelper a)
+        private void VerifyNonEmptyArray(scoped ref Utf8JsonReader r, ref ArrayHelper a)
         {
             Assert.True(a.Next(ref r));
             Assert.Equal(10, r.GetInt32());
@@ -207,7 +207,7 @@ public void EmptyArray()
             VerifyEmptyArray(ref r2, ref a2);
         }
 
-        private void VerifyEmptyArray(ref Utf8JsonReader r, ref ArrayHelper a) =>
+        private void VerifyEmptyArray(scoped ref Utf8JsonReader r, ref ArrayHelper a) =>
             Assert.False(a.Next(ref r));
 
         [Fact]
@@ -242,7 +242,7 @@ public void NonEmptyObject()
             VerifyNonEmptyObject(ref r2, ref o2);
         }
 
-        private void VerifyNonEmptyObject(ref Utf8JsonReader r, ref ObjectHelper o)
+        private void VerifyNonEmptyObject(scoped ref Utf8JsonReader r, ref ObjectHelper o)
         {
             Assert.True(o.Next(ref r));
             Assert.Equal("a", o.Name);
@@ -267,7 +267,7 @@ public void EmptyObject()
             VerifyEmptyObject(ref r2, ref o2);
         }
 
-        private void VerifyEmptyObject(ref Utf8JsonReader r, ref ObjectHelper o) =>
+        private void VerifyEmptyObject(scoped ref Utf8JsonReader r, ref ObjectHelper o) =>
             Assert.False(o.Next(ref r));
 
         [Fact]
diff --git a/test/LaunchDarkly.InternalSdk.Tests/LaunchDarkly.InternalSdk.Tests.csproj b/test/LaunchDarkly.InternalSdk.Tests/LaunchDarkly.InternalSdk.Tests.csproj
index b96b705..61943c7 100644
--- a/test/LaunchDarkly.InternalSdk.Tests/LaunchDarkly.InternalSdk.Tests.csproj
+++ b/test/LaunchDarkly.InternalSdk.Tests/LaunchDarkly.InternalSdk.Tests.csproj
@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TestFramework Condition="'$(TESTFRAMEWORK)' == ''">netcoreapp3.1;net462;net6.0</TestFramework>
+    <TestFramework Condition="'$(TESTFRAMEWORK)' == ''">net462;net8.0</TestFramework>
     <TargetFrameworks>$(TESTFRAMEWORK)</TargetFrameworks>
     <AssemblyName>LaunchDarkly.InternalSdk.Tests</AssemblyName>
     <RootNamespace>LaunchDarkly.Sdk.Internal</RootNamespace>
+    <!-- Match the library's C# 11, needed for the 'scoped' ref-safety annotations. -->
+    <LangVersion>11</LangVersion>
     <Version>1.2.3</Version> <!-- we check for this value in tests -->
     <ReleaseVersion>1.2.3</ReleaseVersion>
     <SynchReleaseVersion>false</SynchReleaseVersion>