diff --git a/modules/mesh-delivery-builder/internal/build/claim.go b/modules/mesh-delivery-builder/internal/build/claim.go
index cb5f74c..d598bc7 100644
--- a/modules/mesh-delivery-builder/internal/build/claim.go
+++ b/modules/mesh-delivery-builder/internal/build/claim.go
@@ -85,9 +85,26 @@ func Unpublished(b delivery.BuilderBuild) bool {
 	return false
 }
 
+// Unreferenced is whether a done build holds a bundle, an archive or an upstream copy that names no reference: a key done
+// before R4e, whose artifacts stayed on their build nodes (ADR 0498 clause 8). An artifact of no kind (a key written before
+// kinds) is one too. Claim takes such a key again, once: its new revision names them.
+func Unreferenced(b delivery.BuilderBuild) bool {
+	if b.State != delivery.BuildDone {
+		return false
+	}
+	for _, a := range b.Artifacts {
+		if a.Reference == "" && (a.Kind == "" || stored(a.Kind)) {
+			return true
+		}
+	}
+	return false
+}
+
 // Claim takes the build of module at fingerprint, or answers nil when it is not this builder's to build now:
 //   - no key: it is created building, by this builder; a create that finds the key made meanwhile gets nothing;
-//   - a done key is not taken again (the same source is never built twice), except one built on one node only (OneNodePrefix)
+//   - a done key is not taken again (the same source is never built twice), except one whose bundle, archive or upstream
+//     copy names no reference (Unreferenced, a key done before R4e: ADR 0498 clause 8), which is claimed building as a new
+//     revision and built whole, and one built on one node only (OneNodePrefix)
 //     when a second node qualifies now (ClaimOptions.MoreNodes): that is taken as it stands, with the done value, and its
 //     builder writes the new revision when the second build ends (ADR 0478 clause 4);
 //   - a failed key is taken again as a new revision of the same key (ADR 0429 clause 18), except one failed for a kind no
@@ -115,6 +132,9 @@ func (c Claimer) Claim(ctx context.Context, module, fingerprint, manifest string
 	}
 	switch {
 	case cur.State == delivery.BuildDone:
+		if Unreferenced(cur) {
+			return c.write(ctx, key, building, func(data []byte) (uint64, error) { return c.Store.Update(ctx, key, data, rev) })
+		}
 		if modules := OneNodeModules(cur); len(modules) > 0 && opt.MoreNodes != nil && opt.MoreNodes(modules) {
 			return &Claim{Key: key, Rev: rev, Build: cur}, nil
 		}
diff --git a/modules/mesh-delivery-builder/internal/build/claim_test.go b/modules/mesh-delivery-builder/internal/build/claim_test.go
index cab71e3..fdf6d93 100644
--- a/modules/mesh-delivery-builder/internal/build/claim_test.go
+++ b/modules/mesh-delivery-builder/internal/build/claim_test.go
@@ -125,9 +125,9 @@ func TestClaimLosingTheCreateRaceGetsNothing(t *testing.T) { // 1607/AC3
 	}
 }
 
-func TestADoneKeyIsNeverTakenAgain(t *testing.T) { // 1607/AC3
+func TestADoneKeyIsNeverTakenAgain(t *testing.T) { // 1607/AC3; a key whose artifacts name references (ADR 0498 clause 8)
 	st := newMem()
-	seed(t, st, delivery.BuilderBuild{State: delivery.BuildDone, By: "novox.a", Manifest: hex64('a'), Artifacts: []delivery.BuiltArtifact{{Name: "x", Digest: digest}}})
+	seed(t, st, delivery.BuilderBuild{State: delivery.BuildDone, By: "novox.a", Manifest: hex64('a'), Artifacts: []delivery.BuiltArtifact{{Name: "x", Kind: "bundle", Digest: digest, Reference: "artifact-store://m/x/blobs/" + digest}}})
 	writes := st.writes
 	got, err := Claimer{Store: st, By: "novox.a"}.Claim(context.Background(), "m", fp1, hex64('a'), ClaimOptions{})
 	if err != nil || got != nil || st.writes != writes {
diff --git a/modules/mesh-delivery-builder/internal/build/r4e_test.go b/modules/mesh-delivery-builder/internal/build/r4e_test.go
index 6d77b9a..ad5b584 100644
--- a/modules/mesh-delivery-builder/internal/build/r4e_test.go
+++ b/modules/mesh-delivery-builder/internal/build/r4e_test.go
@@ -74,3 +74,34 @@ func TestOnlyATrunkKeysBuildsAreAskedToPublish(t *testing.T) { // B1, the lead's
 		}
 	}
 }
+
+// putBuild writes a builder key's value as the store would hold it.
+func putBuild(t *testing.T, st *memStore, key string, b delivery.BuilderBuild) uint64 {
+	t.Helper()
+	data, err := delivery.EncodeBuilderBuild(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	st.mu.Lock()
+	defer st.mu.Unlock()
+	return st.put(key, data)
+}
+
+func TestADoneKeyWrittenBeforeR4eIsBuiltAgainOnceAsANewRevision(t *testing.T) { // B2, ADR 0498 clause 8
+	r := newRig(t, goBundle, archiveA)
+	rev := putBuild(t, r.st, r.key, delivery.BuilderBuild{State: delivery.BuildDone, By: "novox.builder", Manifest: manifestD, Step: "built mesh-build-go on ace and novox",
+		Artifacts: []delivery.BuiltArtifact{{Name: "files", Kind: "archive", Digest: digest}, {Name: "tool", Kind: "bundle", Digest: digest}}})
+	v := r.consider(t, "modules/m")
+	if v.State != delivery.BuildDone || r.st.revs[r.key] <= rev {
+		t.Fatalf("build = %+v at revision %d (was %d), want built again as a new revision", v, r.st.revs[r.key], rev)
+	}
+	if ok, missing := v.Referenced(); !ok {
+		t.Fatalf("the new revision names no reference for %v", missing)
+	}
+	rev = r.st.revs[r.key]
+	r.b.tried = map[string]bool{} // a builder started anew looks again
+	r.consider(t, "modules/m")
+	if r.st.revs[r.key] != rev {
+		t.Errorf("a key whose artifacts all name references was built again (revision %d, was %d): once only", r.st.revs[r.key], rev)
+	}
+}