diff --git a/src/workers/src/Dbosoft.Bote.BoteWorker/Dbosoft.Bote.BoteWorker.csproj b/src/workers/src/Dbosoft.Bote.BoteWorker/Dbosoft.Bote.BoteWorker.csproj
index 4425578..82fff2f 100644
--- a/src/workers/src/Dbosoft.Bote.BoteWorker/Dbosoft.Bote.BoteWorker.csproj
+++ b/src/workers/src/Dbosoft.Bote.BoteWorker/Dbosoft.Bote.BoteWorker.csproj
@@ -34,6 +34,29 @@
     <ProjectReference Include="..\..\..\Dbosoft.Bote.Primitives\Dbosoft.Bote.Primitives.csproj" />
     <ProjectReference Include="..\..\..\Dbosoft.Bote.Rebus.Integration\Dbosoft.Bote.Rebus.Integration.csproj" />
   </ItemGroup>
+  <!--
+    The blob extension the Functions host loads is the one the worker package names: 6.8.2 names
+    5.3.8, whose container scan finds only blobs written before the host's first poll, so attachments
+    from the cloud reach a client only after a restart (Azure/azure-sdk-for-net#61660, fixed in
+    5.3.10). No worker package names 5.3.10 yet and the SDK takes no override, so the generated
+    extension project is pointed at it here. The build fails once the worker package names another
+    version: then this target is to go.
+  -->
+  <PropertyGroup>
+    <_BlobsExtensionNamed>5.3.8</_BlobsExtensionNamed>
+    <_BlobsExtensionFixed>5.3.10</_BlobsExtensionFixed>
+  </PropertyGroup>
+  <Target Name="_PinFixedBlobsExtension" AfterTargets="_FunctionsGenerateCommon" Condition="'$(_FunctionsBuildEnabled)' == 'true'">
+    <PropertyGroup>
+      <_NamedBlobsReference>&lt;PackageReference Include="Microsoft.Azure.WebJobs.Extensions.Storage.Blobs" Version="$(_BlobsExtensionNamed)" /&gt;</_NamedBlobsReference>
+      <_FixedBlobsReference>&lt;PackageReference Include="Microsoft.Azure.WebJobs.Extensions.Storage.Blobs" Version="$(_BlobsExtensionFixed)" /&gt;</_FixedBlobsReference>
+      <_ExtensionsProject>$([System.IO.File]::ReadAllText($(ExtensionsCsProj)))</_ExtensionsProject>
+    </PropertyGroup>
+    <Error Condition="!$(_ExtensionsProject.Contains($(_NamedBlobsReference))) AND !$(_ExtensionsProject.Contains($(_FixedBlobsReference)))"
+           Text="The worker package no longer names blob extension $(_BlobsExtensionNamed); remove _PinFixedBlobsExtension." />
+    <WriteLinesToFile Condition="$(_ExtensionsProject.Contains($(_NamedBlobsReference)))" File="$(ExtensionsCsProj)"
+                      Lines="$([MSBuild]::Escape($(_ExtensionsProject.Replace($(_NamedBlobsReference), $(_FixedBlobsReference)))))" Overwrite="true" WriteOnlyWhenDifferent="true" />
+  </Target>
   <ItemGroup>
     <InternalsVisibleTo Include="Dbosoft.Bote.Rebus.IntegrationTests" />
     <InternalsVisibleTo Include="Dbosoft.Bote.BoteWorker.Tests" />
diff --git a/test/Dbosoft.Bote.BoteWorker.Tests/HostExtensionsTests.cs b/test/Dbosoft.Bote.BoteWorker.Tests/HostExtensionsTests.cs
new file mode 100644
index 0000000..4291060
--- /dev/null
+++ b/test/Dbosoft.Bote.BoteWorker.Tests/HostExtensionsTests.cs
@@ -0,0 +1,20 @@
+using AwesomeAssertions;
+
+namespace Dbosoft.Bote.BoteWorker.Tests;
+
+public class HostExtensionsTests
+{
+    /// <summary>
+    /// Before 5.3.10 the outbox trigger finds only blobs written before the host's first poll: an
+    /// attachment from the cloud then waits for a restart of the worker (Azure/azure-sdk-for-net#61660).
+    /// </summary>
+    [Fact]
+    public void The_host_loads_a_blob_extension_that_finds_new_blobs()
+    {
+        var file = Path.Combine(AppContext.BaseDirectory, ".azurefunctions", "Microsoft.Azure.WebJobs.Extensions.Storage.Blobs.dll");
+        File.Exists(file).Should().BeTrue("the worker's build puts the host's extensions there");
+
+        var version = System.Diagnostics.FileVersionInfo.GetVersionInfo(file).ProductVersion!.Split('+')[0];
+        Version.Parse(version).Should().BeGreaterThanOrEqualTo(new Version(5, 3, 10));
+    }
+}