diff --git a/bitwarden_license/src/Sso/Utilities/DynamicAuthenticationSchemeProvider.cs b/bitwarden_license/src/Sso/Utilities/DynamicAuthenticationSchemeProvider.cs
index db574e71c536..7a26a37f0d09 100644
--- a/bitwarden_license/src/Sso/Utilities/DynamicAuthenticationSchemeProvider.cs
+++ b/bitwarden_license/src/Sso/Utilities/DynamicAuthenticationSchemeProvider.cs
@@ -299,7 +299,7 @@ private DynamicAuthenticationScheme GetOidcAuthenticationScheme(string name, Sso
             ClientId = config.ClientId,
             ClientSecret = config.ClientSecret,
             ResponseType = "code",
-            ResponseMode = "form_post",
+            ResponseMode = "query",
             SignInScheme = AuthenticationSchemes.BitwardenExternalCookieAuthenticationScheme,
             SignOutScheme = IdentityServerConstants.SignoutScheme,
             SaveTokens = false, // reduce overall request size
diff --git a/src/Core/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverter.cs b/src/Core/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverter.cs
new file mode 100644
index 000000000000..65732f8a02c4
--- /dev/null
+++ b/src/Core/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverter.cs
@@ -0,0 +1,63 @@
+using Bit.Core.AdminConsole.Entities;
+using OneOf;
+
+namespace Bit.Core.Billing.Providers.Services.NoopImplementations;
+
+/// <summary>
+/// A no-op implementation of <see cref="IBusinessUnitConverter"/> for use in OSS (non-commercial) builds.
+/// Business unit conversion is a commercial feature and is not available in OSS deployments.
+/// All methods throw <see cref="NotSupportedException"/> to indicate the feature is unavailable.
+/// </summary>
+public class NoopBusinessUnitConverter : IBusinessUnitConverter
+{
+    /// <inheritdoc />
+    /// <exception cref="NotSupportedException">
+    /// Always thrown because business unit conversion is not available in OSS builds.
+    /// </exception>
+    public Task<Guid> FinalizeConversion(
+        Organization organization,
+        Guid userId,
+        string token,
+        string providerKey,
+        string organizationKey)
+    {
+        throw new NotSupportedException(
+            "Business unit conversion is not available in non-commercial Bitwarden builds.");
+    }
+
+    /// <inheritdoc />
+    /// <exception cref="NotSupportedException">
+    /// Always thrown because business unit conversion is not available in OSS builds.
+    /// </exception>
+    public Task<OneOf<Guid, List<string>>> InitiateConversion(
+        Organization organization,
+        string providerAdminEmail)
+    {
+        throw new NotSupportedException(
+            "Business unit conversion is not available in non-commercial Bitwarden builds.");
+    }
+
+    /// <inheritdoc />
+    /// <exception cref="NotSupportedException">
+    /// Always thrown because business unit conversion is not available in OSS builds.
+    /// </exception>
+    public Task ResendConversionInvite(
+        Organization organization,
+        string providerAdminEmail)
+    {
+        throw new NotSupportedException(
+            "Business unit conversion is not available in non-commercial Bitwarden builds.");
+    }
+
+    /// <inheritdoc />
+    /// <exception cref="NotSupportedException">
+    /// Always thrown because business unit conversion is not available in OSS builds.
+    /// </exception>
+    public Task ResetConversion(
+        Organization organization,
+        string providerAdminEmail)
+    {
+        throw new NotSupportedException(
+            "Business unit conversion is not available in non-commercial Bitwarden builds.");
+    }
+}
diff --git a/src/SharedWeb/Utilities/ServiceCollectionExtensions.cs b/src/SharedWeb/Utilities/ServiceCollectionExtensions.cs
index 8d65547f7621..1d8666de7eaf 100644
--- a/src/SharedWeb/Utilities/ServiceCollectionExtensions.cs
+++ b/src/SharedWeb/Utilities/ServiceCollectionExtensions.cs
@@ -23,6 +23,8 @@
 using Bit.Core.Auth.UserFeatures;
 using Bit.Core.Auth.UserFeatures.EmergencyAccess;
 using Bit.Core.Auth.UserFeatures.PasswordValidation;
+using Bit.Core.Billing.Providers.Services;
+using Bit.Core.Billing.Providers.Services.NoopImplementations;
 using Bit.Core.Billing.Services;
 using Bit.Core.Billing.Services.Implementations;
 using Bit.Core.Billing.TrialInitiation;
@@ -366,6 +368,7 @@ public static void AddDefaultServices(this IServiceCollection services, GlobalSe
     public static void AddOosServices(this IServiceCollection services)
     {
         services.AddScoped<IProviderService, NoopProviderService>();
+        services.AddTransient<IBusinessUnitConverter, NoopBusinessUnitConverter>();
         services.AddScoped<IServiceAccountRepository, NoopServiceAccountRepository>();
         services.AddScoped<ISecretRepository, NoopSecretRepository>();
         services.AddScoped<ISecretVersionRepository, NoopSecretVersionRepository>();
diff --git a/test/Core.Test/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverterTests.cs b/test/Core.Test/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverterTests.cs
new file mode 100644
index 000000000000..814d8a8ece33
--- /dev/null
+++ b/test/Core.Test/Billing/Providers/Services/NoopImplementations/NoopBusinessUnitConverterTests.cs
@@ -0,0 +1,63 @@
+using Bit.Core.AdminConsole.Entities;
+using Bit.Core.Billing.Providers.Services.NoopImplementations;
+using Xunit;
+
+namespace Bit.Core.Test.Billing.Providers.Services.NoopImplementations;
+
+public class NoopBusinessUnitConverterTests
+{
+    private readonly NoopBusinessUnitConverter _sut = new();
+
+    [Fact]
+    public async Task FinalizeConversion_ThrowsNotSupportedException()
+    {
+        var organization = new Organization();
+
+        await Assert.ThrowsAsync<NotSupportedException>(
+            () => _sut.FinalizeConversion(
+                organization,
+                Guid.NewGuid(),
+                "token",
+                "providerKey",
+                "organizationKey"));
+    }
+
+    [Fact]
+    public async Task InitiateConversion_ThrowsNotSupportedException()
+    {
+        var organization = new Organization();
+
+        await Assert.ThrowsAsync<NotSupportedException>(
+            () => _sut.InitiateConversion(
+                organization,
+                "admin@example.com"));
+    }
+
+    [Fact]
+    public async Task ResendConversionInvite_ThrowsNotSupportedException()
+    {
+        var organization = new Organization();
+
+        await Assert.ThrowsAsync<NotSupportedException>(
+            () => _sut.ResendConversionInvite(
+                organization,
+                "admin@example.com"));
+    }
+
+    [Fact]
+    public async Task ResetConversion_ThrowsNotSupportedException()
+    {
+        var organization = new Organization();
+
+        await Assert.ThrowsAsync<NotSupportedException>(
+            () => _sut.ResetConversion(
+                organization,
+                "admin@example.com"));
+    }
+
+    [Fact]
+    public void ImplementsIBusinessUnitConverter()
+    {
+        Assert.IsAssignableFrom<IBusinessUnitConverter>(_sut);
+    }
+}