diff --git a/services/activitylog/pkg/service/migrations.go b/services/activitylog/pkg/service/migrations.go
new file mode 100644
index 000000000..95356424d
--- /dev/null
+++ b/services/activitylog/pkg/service/migrations.go
@@ -0,0 +1,135 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+
+	"github.com/nats-io/nats.go"
+	"github.com/vmihailenco/msgpack/v5"
+)
+
+const activitylogVersionKey = "activilog.version"
+const currentMigrationVersion = "1"
+
+// RunMigrations checks the activilog data version and runs migrations if necessary.
+// It should be called during service startup, after the NATS KeyValue store is initialized.
+func runMigrations(ctx context.Context, kv nats.KeyValue) error {
+	entry, err := kv.Get(activitylogVersionKey)
+	if err == nats.ErrKeyNotFound {
+		// Key doesn't exist, version is implicitly pre-V1. Run migration to V1.
+		log.Println("Activilog version key not found. Running migration to V1...")
+		return migrateToV1(ctx, kv)
+	} else if err != nil {
+		return fmt.Errorf("failed to get activilog version from NATS KV store: %w", err)
+	}
+
+	version := string(entry.Value())
+	if version == currentMigrationVersion {
+		log.Printf("Activilog data version is '%s'. No migration needed.", version)
+		return nil
+	}
+
+	// If version is something else, it might indicate a future version or an unexpected state.
+	// Add logic here if more complex version handling is needed.
+	log.Printf("Activilog data version is '%s', expected '%s'. Migration logic for this scenario is not implemented.", version, currentMigrationVersion)
+	return fmt.Errorf("unexpected activilog version: %s, expected %s", version, currentMigrationVersion)
+}
+
+// migrateToV1 performs the data migration to version 1.
+// It iterates over all keys, expecting their values to be JSON arrays of strings.
+// For each such key, it creates a new key in the format "originalKey:count:timestamp"
+// and stores the original list of strings (re-marshalled to JSON) as its value.
+// Finally, it sets the activilog.version key to "1".
+func migrateToV1(_ context.Context, kv nats.KeyValue) error {
+	lister, err := kv.ListKeys()
+	if err != nil {
+		return fmt.Errorf("migrateToV1: failed to list keys from NATS KV store: %w", err)
+	}
+
+	migratedCount := 0
+	skippedCount := 0
+
+	keyChan := lister.Keys()
+	defer lister.Stop()
+
+	// keyValueEnvelope is the data structure used by the go micro plugin which was used previously.
+	type keyValueEnvelope struct {
+		Key      string                 `json:"key"`
+		Data     []byte                 `json:"data"`
+		Metadata map[string]interface{} `json:"metadata"`
+	}
+
+	for key := range keyChan {
+		if key == activitylogVersionKey {
+			skippedCount++
+			continue // Skip the version key itself
+		}
+
+		// Get the original value
+		entry, err := kv.Get(key)
+		if err == nats.ErrKeyNotFound {
+			log.Printf("migrateToV1: Key '%s' disappeared during migration, skipping.", key)
+			skippedCount++
+			continue
+		} else if err != nil {
+			log.Printf("migrateToV1: Failed to get value for key '%s': %v. Skipping.", key, err)
+			skippedCount++
+			continue
+		}
+		valBytes := entry.Value()
+
+		val := keyValueEnvelope{}
+		// Unmarshal the value into the keyValueEnvelope structure
+		if err := json.Unmarshal(valBytes, &val); err != nil {
+			log.Printf("migrateToV1: Value for key '%s' is not a keyValueEnvelope: %v. Skipping.", key, err)
+			skippedCount++
+		}
+
+		// Unmarshal value into a list of strings
+		var activities []RawActivity
+		if err := msgpack.Unmarshal(val.Data, &activities); err != nil {
+			if err := json.Unmarshal(val.Data, &activities); err != nil {
+				// This key's value is not a JSON array of strings. Skip it.
+				log.Printf("migrateToV1: Value for key '%s' is not a msgback or JSON array of strings: %v. Skipping.", key, err)
+				skippedCount++
+				continue
+			}
+		}
+
+		// Construct the new key
+		newKey := natsKey(val.Key, len(activities))
+		newValue, err := msgpack.Marshal(activities)
+		if err != nil {
+			log.Printf("migrateToV1: Failed to marshal activities for key '%s': %v. Skipping.", key, err)
+			skippedCount++
+			continue
+		}
+
+		// Write the value (the list of strings, marshalled as JSON) under the new key
+		if _, err := kv.Put(newKey, newValue); err != nil {
+			log.Printf("migrateToV1: Failed to put new key '%s' (original key '%s') in NATS KV store: %v. Skipping.", newKey, key, err)
+			skippedCount++
+			continue
+		}
+
+		// delete old key, it's no longer needed
+		if err := kv.Delete(key); err != nil {
+			log.Printf("migrateToV1: Failed to delete old key '%s' after migration: %v. Skipping deletion.", key, err)
+			skippedCount++
+			continue
+		}
+
+		log.Printf("migrateToV1: Migrated key '%s' to '%s' with %d elements.", key, newKey, len(activities))
+		migratedCount++
+	}
+
+	// Set the activilog version to "1" after migration
+	if _, err := kv.PutString(activitylogVersionKey, currentMigrationVersion); err != nil {
+		return fmt.Errorf("migrateToV1: failed to set activilog version key to '%s' in NATS KV store: %w", currentMigrationVersion, err)
+	}
+
+	log.Printf("Migration to V1 complete. Migrated %d keys, skipped %d keys. Activilog version set to '%s'.", migratedCount, skippedCount, currentMigrationVersion)
+	return nil
+}
diff --git a/services/activitylog/pkg/service/service.go b/services/activitylog/pkg/service/service.go
index a0cd0a3cb..75889ba29 100644
--- a/services/activitylog/pkg/service/service.go
+++ b/services/activitylog/pkg/service/service.go
@@ -193,6 +193,12 @@ func New(opts ...Option) (*ActivitylogService, error) {
 		return nil, err
 	}
 
+	// run migrations
+	err = runMigrations(context.Background(), kv)
+	if err != nil {
+		return nil, err
+	}
+
 	s := &ActivitylogService{
 		log:              o.Logger,
 		cfg:              o.Config,
@@ -510,7 +516,7 @@ func (a *ActivitylogService) storeActivity(resourceID string, activities []RawAc
 	subspan.End()
 
 	_, subspan = a.tracer.Start(ctx, "storeActivity.natskv.Put")
-	key := a.natsKey(resourceID, len(activities))
+	key := natsKey(resourceID, len(activities))
 	_, err = a.natskv.Put(key, b)
 	if err != nil {
 		return err
@@ -523,13 +529,6 @@ func (a *ActivitylogService) storeActivity(resourceID string, activities []RawAc
 	return nil
 }
 
-func (a *ActivitylogService) natsKey(resourceID string, activitiesCount int) string {
-	return fmt.Sprintf("%s.%d.%d",
-		base32.StdEncoding.EncodeToString([]byte(resourceID)),
-		activitiesCount,
-		time.Now().UnixNano())
-}
-
 func (a *ActivitylogService) enforceMaxActivities(ctx context.Context, resourceID string) {
 	if a.maxActivities <= 0 {
 		return
@@ -651,3 +650,10 @@ func (a *ActivitylogService) removeCachedParentID(ref *provider.Reference) {
 		a.log.Error().Interface("event", ref).Err(err).Msg("could not delete parent id cache")
 	}
 }
+
+func natsKey(resourceID string, activitiesCount int) string {
+	return fmt.Sprintf("%s.%d.%d",
+		base32.StdEncoding.EncodeToString([]byte(resourceID)),
+		activitiesCount,
+		time.Now().UnixNano())
+}