diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
index 767449fe..788b6fa6 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
@@ -485,6 +485,23 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		}
 		defer pc.Stop()
 	}
+	// The versions each package's series holds (DLV-I5): the registry seats' published and the builder's numbered, on the
+	// indexer's durable consumer of the shared events stream. Where it is not there yet, no series moves until the indexer
+	// starts again, said.
+	switch vcons, err := cred.EventConsumer(ctx, js, process.EventsStream); {
+	case err != nil:
+		logger.Printf("the consumer %s_%s on %s does not exist yet, so no package's series moves until the indexer starts again: %v", cred.Node, cred.Module, process.EventsStream, err)
+	default:
+		vc, err := process.HearEvents(vcons, func(m jetstream.Msg) {
+			if !heardVersion(ctx, ix, m, logger.Printf) {
+				_ = m.Ack() // nothing else the indexer consumes rides the shared stream
+			}
+		}, logger.Printf)
+		if err != nil {
+			return err
+		}
+		defer vc.Stop()
+	}
 	cons, err := cred.EventConsumer(ctx, js, forgeStream)
 	if err != nil {
 		// Essential: the forge's merges are what the indexer indexes.
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/series.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/series.go
new file mode 100644
index 00000000..3d030bb1
--- /dev/null
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/series.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-contracts/go/seats/gopackageregistry"
+	"git.novox.be/novox/mesh-contracts/go/seats/npmpackageregistry"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+
+	"mesh-delivery-indexer/internal/index"
+)
+
+// The versions the packages state keeps per series (index.HearVersion, DLV-I5), heard on the indexer's durable consumer of
+// the shared events stream: the package registry seats' published (their contracts in mesh-contracts) and the builder's
+// numbered (its own event, version.numbered).
+var (
+	publishedSeats = map[string]string{
+		gopackageregistry.SubjectPublished:  gopackageregistry.Seat,
+		npmpackageregistry.SubjectPublished: npmpackageregistry.Seat,
+	}
+	numberedSubject = "mesh.mod." + delivery.BuilderModule + ".event.version.numbered"
+)
+
+// numbered is the builder's version.numbered body as the indexer reads it.
+type numbered struct {
+	Name        string `json:"name"`
+	Kind        string `json:"kind"`
+	Version     string `json:"version"`
+	Tag         string `json:"tag,omitempty"`
+	Fingerprint string `json:"fingerprint"`
+	Commit      string `json:"commit,omitempty"`
+	Digest      string `json:"digest,omitempty"`
+	Seat        string `json:"seat,omitempty"`
+}
+
+// heardVersion reads one message of the consumer as a version, false for any other subject. A package's is kept in its
+// series; one that does not decode is said and acknowledged; a write that fails is left unacknowledged, so the bus gives
+// it again.
+func heardVersion(ctx context.Context, ix *index.Indexer, m jetstream.Msg, logf func(string, ...any)) bool {
+	var h index.HeardVersion
+	switch seat, ok := publishedSeats[m.Subject()]; {
+	case ok:
+		var p gopackageregistry.PublishedEvent // both seats' published are the same Outcome
+		if err := json.Unmarshal(m.Data(), &p); err != nil {
+			logf("%s holds what is no published of %s, left: %v", m.Subject(), seat, err)
+			_ = m.Ack()
+			return true
+		}
+		if p.Kind != "package" {
+			_ = m.Ack()
+			return true
+		}
+		h = index.HeardVersion{Package: p.Name, Seat: seat, Version: p.Version, Tag: p.Tag, Commit: p.Commit, Digest: p.Digest,
+			Fingerprint: p.Fingerprint, GoModule: p.Module, Published: true}
+	case m.Subject() == numberedSubject:
+		var n numbered
+		if err := json.Unmarshal(m.Data(), &n); err != nil {
+			logf("%s holds what is no numbered, left: %v", m.Subject(), err)
+			_ = m.Ack()
+			return true
+		}
+		if n.Kind != "package" {
+			_ = m.Ack()
+			return true
+		}
+		h = index.HeardVersion{Package: n.Name, Seat: n.Seat, Version: n.Version, Tag: n.Tag, Commit: n.Commit, Digest: n.Digest,
+			Fingerprint: n.Fingerprint}
+	default:
+		return false
+	}
+	kept, err := ix.HearVersion(ctx, h)
+	if err != nil {
+		logf("%s of %s %s could not be kept in its series, so the bus gives it again: %v", m.Subject(), h.Package, h.Version, err)
+		return true
+	}
+	if kept {
+		logf("packages: %s %s kept in its series (published %v)", h.Package, h.Version, h.Published)
+	}
+	_ = m.Ack()
+	return true
+}
diff --git a/modules/mesh-delivery-indexer/go.mod b/modules/mesh-delivery-indexer/go.mod
index 4c66d058..610c5508 100644
--- a/modules/mesh-delivery-indexer/go.mod
+++ b/modules/mesh-delivery-indexer/go.mod
@@ -26,4 +26,9 @@ replace git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun
 
 require git.novox.be/novox/mesh-delivery/sdk v0.0.0-00010101000000-000000000000
 
+require (
+	git.novox.be/novox/mesh-contracts/go/seats/gopackageregistry v0.0.0-00010101000000-000000000000
+	git.novox.be/novox/mesh-contracts/go/seats/npmpackageregistry v0.0.0-00010101000000-000000000000
+)
+
 replace git.novox.be/novox/mesh-delivery/sdk => ../../sdk
diff --git a/modules/mesh-delivery-indexer/internal/index/control_records_test.go b/modules/mesh-delivery-indexer/internal/index/control_records_test.go
index 55d50126..3102e381 100644
--- a/modules/mesh-delivery-indexer/internal/index/control_records_test.go
+++ b/modules/mesh-delivery-indexer/internal/index/control_records_test.go
@@ -109,6 +109,35 @@ func TestTheControlRecords(t *testing.T) {
 			t.Errorf("none = %#v, want an empty list", got)
 		}
 	})
+	// DLV-I5 (milestone § 2 item 1, design 51 *The versions*): a package's series key keeps the newest trunk version the
+	// builder numbered and the newest a seat published; an older one, a tagged one and one of another series move neither;
+	// the per-module digests never read a series key.
+	t.Run("packages per series", func(t *testing.T) {
+		ctx := context.Background()
+		ix := &Indexer{Packages: newMem()}
+		sdkGo := "git.novox.be/novox/mesh-sdk/go"
+		for _, h := range []HeardVersion{
+			{Package: "mesh-sdk/go", Seat: "go-package-registry", Version: "0.1.15", Commit: "c15"},
+			{Package: "mesh-sdk/go", Seat: "go-package-registry", Version: "0.1.15", Commit: "c15", Digest: "h1:a", GoModule: sdkGo, Published: true},
+			{Package: "mesh-sdk/go", Version: "0.1.16", Commit: "c16"},
+			{Package: "mesh-sdk/go", Version: "0.1.14", Commit: "c14", Published: true},
+			{Package: "mesh-sdk/go", Version: "0.1.17-feat-x.1", Tag: "feat-x", Published: true},
+			{Package: "mesh-sdk/go", Version: "0.2.0", Commit: "c20", Published: true},
+		} {
+			if _, err := ix.HearVersion(ctx, h); err != nil {
+				t.Fatal(err)
+			}
+		}
+		all := ix.SeriesAll(ctx)
+		one, two := all[SeriesKey("mesh-sdk/go", "0.1")], all[SeriesKey("mesh-sdk/go", "0.2")]
+		if one.Newest == nil || one.Newest.Version != "0.1.15" || one.Newest.Digest != "h1:a" || one.Numbered == nil || one.Numbered.Version != "0.1.16" ||
+			one.GoModule != sdkGo || one.Seat != "go-package-registry" || len(all) != 2 || two.Newest == nil || two.Newest.Version != "0.2.0" {
+			t.Errorf("series = %+v", all)
+		}
+		if got := ix.publishedAll(ctx); len(got) != 0 {
+			t.Errorf("the per-module digests read a series key: %v", got)
+		}
+	})
 	ctx := context.Background()
 	at := time.Date(2026, 10, 29, 22, 0, 0, 0, time.UTC)
 	t.Run("the predefined list, never replaced by an older merge", func(t *testing.T) {
diff --git a/modules/mesh-delivery-indexer/internal/index/packages.go b/modules/mesh-delivery-indexer/internal/index/packages.go
index de1f0e73..84a2ba7a 100644
--- a/modules/mesh-delivery-indexer/internal/index/packages.go
+++ b/modules/mesh-delivery-indexer/internal/index/packages.go
@@ -36,6 +36,9 @@ func (ix *Indexer) publishedAll(ctx context.Context) map[string]delivery.Publish
 		return out
 	}
 	for _, key := range keys {
+		if IsSeriesKey(key) {
+			continue // a package's series (series.go), not a Go module's digests
+		}
 		value, _, found, err := ix.Packages.Get(ctx, key)
 		if err != nil || !found {
 			continue
diff --git a/modules/mesh-delivery-indexer/internal/index/series.go b/modules/mesh-delivery-indexer/internal/index/series.go
new file mode 100644
index 00000000..84dc9bdf
--- /dev/null
+++ b/modules/mesh-delivery-indexer/internal/index/series.go
@@ -0,0 +1,142 @@
+package index
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// The packages state per series (DLV-I5; milestone § 2 item 1; design 51 *The versions*, ADR 0606 §1, ADR 0609 §1): beside
+// the per-module digests (packages.go, ADR 0593 §2), one key per package and series, `<package>.<series>`, holding the newest
+// trunk version of that series the builder numbered and the newest a registry seat published. It is filled from the
+// builder's `version.numbered` and the package registry seats' `published`, never from a timer; `indexer_requirements`,
+// the fingerprint input and `indexer_package_users` read it. A tagged version (a group's) is never a series' newest.
+//
+// A series key always holds a dot (`mesh-sdk/go.0.1`), which EscapeName never leaves in a per-module key: a reader tells the
+// two forms apart by IsSeriesKey.
+
+// SeriesPackage is the value of a series key.
+type SeriesPackage struct {
+	V int `json:"v"`
+	// Package is the builder's name of the package, `<module>/<artifact>`; Series its `<major>.<minor>`.
+	Package string `json:"package"`
+	Series  string `json:"series"`
+	// Seat is the registry seat it is published through; GoModule the Go module path a Go package is fetched under (from
+	// go-package-registry's published), empty for any other.
+	Seat     string `json:"seat,omitempty"`
+	GoModule string `json:"go-module,omitempty"`
+	// Newest is the newest version of the series a seat published: what a user accepting the series builds against.
+	Newest *SeriesVersion `json:"newest,omitempty"`
+	// Numbered is the newest version of the series the builder numbered, published or not yet.
+	Numbered *SeriesVersion `json:"numbered,omitempty"`
+	At       time.Time      `json:"at"`
+}
+
+// SeriesVersion is one version of a series: its number, the source commit it was built from, the digest and fingerprint.
+type SeriesVersion struct {
+	Version     string `json:"version"`
+	Commit      string `json:"commit,omitempty"`
+	Digest      string `json:"digest,omitempty"`
+	Fingerprint string `json:"fingerprint,omitempty"`
+}
+
+// SeriesKey is the key of a package's series in the packages state.
+func SeriesKey(pkg, series string) string { return delivery.EscapeName(pkg) + "." + series }
+
+// IsSeriesKey says whether a key of the packages state is a series key, not a per-module one.
+func IsSeriesKey(key string) bool { return strings.Contains(key, ".") }
+
+// SeriesOf is the series of a trunk version (`0.1.15` is of `0.1`); false for a version that is no `<major>.<minor>.<patch>`
+// or that carries a tag (a pre-release).
+func SeriesOf(version string) (string, bool) {
+	p, ok := semverParts("v" + strings.TrimPrefix(version, "v"))
+	if !ok || p.pre != "" {
+		return "", false
+	}
+	return fmt.Sprintf("%d.%d", p.core[0], p.core[1]), true
+}
+
+// HeardVersion is what the indexer takes of a numbered or a published: the package's name, the seat, the version and its
+// tag, the commit, digest and fingerprint, and the Go module path a published names.
+type HeardVersion struct {
+	Package, Seat, Version, Tag, Commit, Digest, Fingerprint, GoModule string
+	// Published is true for a seat's published, false for the builder's numbered.
+	Published bool
+}
+
+// HearVersion keeps a trunk version in its series' key: as the series' newest numbered, and, once published, as its newest.
+// A tagged version, a version that does not read and an older one than held are passed over (false). Nil Packages keeps
+// nothing.
+func (ix *Indexer) HearVersion(ctx context.Context, h HeardVersion) (bool, error) {
+	series, ok := SeriesOf(h.Version)
+	if ix.Packages == nil || h.Package == "" || h.Tag != "" || !ok {
+		return false, nil
+	}
+	v := &SeriesVersion{Version: strings.TrimPrefix(h.Version, "v"), Commit: h.Commit, Digest: h.Digest, Fingerprint: h.Fingerprint}
+	newer := func(held *SeriesVersion) bool {
+		return held == nil || CompareVersions("v"+held.Version, "v"+v.Version) < 0
+	}
+	kept := false
+	err := write(ctx, ix.Packages, SeriesKey(h.Package, series), func(value []byte, found bool) ([]byte, bool, error) {
+		s := SeriesPackage{V: delivery.Version, Package: h.Package, Series: series}
+		if found {
+			if err := json.Unmarshal(value, &s); err != nil {
+				ix.logf("packages.%s holds what is not a series, written anew: %v", SeriesKey(h.Package, series), err)
+				s = SeriesPackage{V: delivery.Version, Package: h.Package, Series: series}
+			}
+		}
+		kept = false
+		if newer(s.Numbered) {
+			s.Numbered, kept = v, true
+		}
+		if h.Published && newer(s.Newest) {
+			s.Newest, kept = v, true
+		}
+		if h.Seat != "" && s.Seat != h.Seat {
+			s.Seat, kept = h.Seat, true
+		}
+		if h.GoModule != "" && s.GoModule != h.GoModule {
+			s.GoModule, kept = h.GoModule, true
+		}
+		if !kept {
+			return nil, false, nil
+		}
+		s.At = ix.now()
+		next, err := json.Marshal(s)
+		return next, false, err
+	})
+	return kept && err == nil, err
+}
+
+// SeriesAll is every series key of the packages state, by key; empty with no state or one that does not answer.
+func (ix *Indexer) SeriesAll(ctx context.Context) map[string]SeriesPackage {
+	out := map[string]SeriesPackage{}
+	if ix.Packages == nil {
+		return out
+	}
+	keys, err := ix.Packages.Keys(ctx)
+	if err != nil {
+		ix.logf("the packages state cannot be listed, so no series is read: %v", err)
+		return out
+	}
+	for _, key := range keys {
+		if !IsSeriesKey(key) {
+			continue
+		}
+		value, _, found, err := ix.Packages.Get(ctx, key)
+		if err != nil || !found {
+			continue
+		}
+		var s SeriesPackage
+		if err := json.Unmarshal(value, &s); err != nil {
+			ix.logf("packages.%s holds what is not a series, left out: %v", key, err)
+			continue
+		}
+		out[key] = s
+	}
+	return out
+}
diff --git a/modules/mesh-delivery-indexer/manifest_test.go b/modules/mesh-delivery-indexer/manifest_test.go
index 71cb3ef8..7e5f5ca9 100644
--- a/modules/mesh-delivery-indexer/manifest_test.go
+++ b/modules/mesh-delivery-indexer/manifest_test.go
@@ -123,7 +123,9 @@ func TestManifestDeclarations(t *testing.T) { // 1238/AC1, 1444 (reads the build
 	}
 	// "Reads FORGE" is a consumes of the indexer's stream: the broker grants only buckets by reads (mesh-control
 	// internal/broker/state.go:62-93).
-	if want := []string{"mesh-build-go.toolchain.reported", "mesh-build-node.toolchain.reported", "mesh-delivery-assigner.views.placement", "mesh-delivery-checker.preview.written", "mesh-delivery-forge-bridge.forge.**"}; !reflect.DeepEqual(sorted(m.Consumes), want) {
+	// The registry seats' published and the builder's numbered fill each package's series (DLV-I5, design 51 *The versions*).
+	if want := []string{"go-package-registry.published", "mesh-build-go.toolchain.reported", "mesh-build-node.toolchain.reported", "mesh-delivery-assigner.views.placement",
+		"mesh-delivery-builder.version.numbered", "mesh-delivery-checker.preview.written", "mesh-delivery-forge-bridge.forge.**", "npm-package-registry.published"}; !reflect.DeepEqual(sorted(m.Consumes), want) {
 		t.Errorf("consumes = %v, want %v", m.Consumes, want)
 	}
 	if b, ok := m.OwnSecrets["broker"]; !ok || len(m.OwnSecrets) != 1 || b != "${dir:state}/broker" {
diff --git a/modules/mesh-delivery-indexer/module.json b/modules/mesh-delivery-indexer/module.json
index e19baaf6..8c449c4a 100644
--- a/modules/mesh-delivery-indexer/module.json
+++ b/modules/mesh-delivery-indexer/module.json
@@ -40,11 +40,14 @@
     "indexer_requirements"
   ],
   "consumes": [
+    "go-package-registry.published",
     "mesh-build-go.toolchain.reported",
     "mesh-build-node.toolchain.reported",
     "mesh-delivery-assigner.views.placement",
+    "mesh-delivery-builder.version.numbered",
     "mesh-delivery-checker.preview.written",
-    "mesh-delivery-forge-bridge.forge.**"
+    "mesh-delivery-forge-bridge.forge.**",
+    "npm-package-registry.published"
   ],
   "state": [
     { "name": "candidates", "history": 10 },