diff --git a/protocol/pushnotificationserver/persistence.go b/protocol/pushnotificationserver/persistence.go
index d0638c6ae..b8de8a04f 100644
--- a/protocol/pushnotificationserver/persistence.go
+++ b/protocol/pushnotificationserver/persistence.go
@@ -16,9 +16,14 @@ type Persistence interface {
 	GetPushNotificationRegistrationByPublicKeyAndInstallationID(publicKey []byte, installationID string) (*protobuf.PushNotificationRegistration, error)
 	// GetPushNotificationRegistrationByPublicKey retrieve all the push notification registrations from storage given a public key
 	GetPushNotificationRegistrationByPublicKeys(publicKeys [][]byte) ([]*PushNotificationIDAndRegistration, error)
-	//GetPushNotificationRegistrationPublicKeys return all the public keys stored
+	// GetPushNotificationRegistrationPublicKeys return all the public keys stored
 	GetPushNotificationRegistrationPublicKeys() ([][]byte, error)
 
+	//GetPushNotificationRegistrationVersion returns the latest version or 0 for a given pk and installationID
+	GetPushNotificationRegistrationVersion(publicKey []byte, installationID string) (uint64, error)
+	// UnregisterPushNotificationRegistration unregister a given pk/installationID
+	UnregisterPushNotificationRegistration(publicKey []byte, installationID string, version uint64) error
+
 	// DeletePushNotificationRegistration deletes a push notification registration from storage given a public key and installation id
 	DeletePushNotificationRegistration(publicKey []byte, installationID string) error
 	// SavePushNotificationRegistration saves a push notification option to the db
@@ -39,8 +44,7 @@ func NewSQLitePersistence(db *sql.DB) Persistence {
 
 func (p *SQLitePersistence) GetPushNotificationRegistrationByPublicKeyAndInstallationID(publicKey []byte, installationID string) (*protobuf.PushNotificationRegistration, error) {
 	var marshaledRegistration []byte
-	var version uint64
-	err := p.db.QueryRow(`SELECT version,registration FROM push_notification_server_registrations WHERE public_key = ? AND installation_id = ?`, publicKey, installationID).Scan(&version, &marshaledRegistration)
+	err := p.db.QueryRow(`SELECT registration FROM push_notification_server_registrations WHERE public_key = ? AND installation_id = ? AND registration IS NOT NULL`, publicKey, installationID).Scan(&marshaledRegistration)
 
 	if err == sql.ErrNoRows {
 		return nil, nil
@@ -48,21 +52,25 @@ func (p *SQLitePersistence) GetPushNotificationRegistrationByPublicKeyAndInstall
 		return nil, err
 	}
 
-	registration := &protobuf.PushNotificationRegistration{
-		InstallationId: installationID,
-		Version:        version,
-	}
-
-	if marshaledRegistration == nil {
-		return registration, nil
-	}
-
+	registration := &protobuf.PushNotificationRegistration{}
 	if err := proto.Unmarshal(marshaledRegistration, registration); err != nil {
 		return nil, err
 	}
 	return registration, nil
 }
 
+func (p *SQLitePersistence) GetPushNotificationRegistrationVersion(publicKey []byte, installationID string) (uint64, error) {
+	registration, err := p.GetPushNotificationRegistrationByPublicKeyAndInstallationID(publicKey, installationID)
+	if err != nil {
+		return 0, err
+	}
+
+	if registration == nil {
+		return 0, nil
+	}
+	return registration.Version, nil
+}
+
 type PushNotificationIDAndRegistration struct {
 	ID           []byte
 	Registration *protobuf.PushNotificationRegistration
@@ -78,7 +86,7 @@ func (p *SQLitePersistence) GetPushNotificationRegistrationByPublicKeys(publicKe
 
 	inVector := strings.Repeat("?, ", len(publicKeys)-1) + "?"
 
-	rows, err := p.db.Query(`SELECT public_key,registration FROM push_notification_server_registrations WHERE public_key IN (`+inVector+`)`, publicKeyArgs...) // nolint: gosec
+	rows, err := p.db.Query(`SELECT public_key,registration FROM push_notification_server_registrations WHERE registration IS NOT NULL AND public_key IN (`+inVector+`)`, publicKeyArgs...) // nolint: gosec
 	if err != nil {
 		return nil, err
 	}
@@ -138,6 +146,11 @@ func (p *SQLitePersistence) SavePushNotificationRegistration(publicKey []byte, r
 	return err
 }
 
+func (p *SQLitePersistence) UnregisterPushNotificationRegistration(publicKey []byte, installationID string, version uint64) error {
+	_, err := p.db.Exec(`UPDATE push_notification_server_registrations SET registration = NULL, version = ? WHERE public_key = ? AND installation_id = ?`, version, publicKey, installationID)
+	return err
+}
+
 func (p *SQLitePersistence) DeletePushNotificationRegistration(publicKey []byte, installationID string) error {
 	_, err := p.db.Exec(`DELETE FROM push_notification_server_registrations WHERE public_key = ? AND installation_id = ?`, publicKey, installationID)
 	return err
diff --git a/protocol/pushnotificationserver/server.go b/protocol/pushnotificationserver/server.go
index cad6a4331..8549c9c3e 100644
--- a/protocol/pushnotificationserver/server.go
+++ b/protocol/pushnotificationserver/server.go
@@ -233,12 +233,12 @@ func (s *Server) validateRegistration(publicKey *ecdsa.PublicKey, payload []byte
 		return nil, ErrMalformedPushNotificationRegistrationInstallationID
 	}
 
-	previousRegistration, err := s.persistence.GetPushNotificationRegistrationByPublicKeyAndInstallationID(common.HashPublicKey(publicKey), registration.InstallationId)
+	previousVersion, err := s.persistence.GetPushNotificationRegistrationVersion(common.HashPublicKey(publicKey), registration.InstallationId)
 	if err != nil {
 		return nil, err
 	}
 
-	if previousRegistration != nil && registration.Version <= previousRegistration.Version {
+	if registration.Version <= previousVersion {
 		return nil, ErrInvalidPushNotificationRegistrationVersion
 	}
 
@@ -290,6 +290,7 @@ func (s *Server) buildPushNotificationQueryResponse(query *protobuf.PushNotifica
 	for _, idAndResponse := range registrations {
 
 		registration := idAndResponse.Registration
+
 		info := &protobuf.PushNotificationQueryInfo{
 			PublicKey:      idAndResponse.ID,
 			Grant:          registration.Grant,
@@ -336,7 +337,7 @@ func (s *Server) buildPushNotificationRequestResponseAndSendNotification(request
 		if err != nil {
 			s.config.Logger.Error("failed to retrieve registration", zap.Error(err))
 			report.Error = protobuf.PushNotificationReport_UNKNOWN_ERROR_TYPE
-		} else if registration == nil || registration.AccessToken == "" {
+		} else if registration == nil {
 			s.config.Logger.Warn("empty registration")
 			report.Error = protobuf.PushNotificationReport_NOT_REGISTERED
 		} else if registration.AccessToken != pn.AccessToken {
@@ -404,11 +405,7 @@ func (s *Server) buildPushNotificationRegistrationResponse(publicKey *ecdsa.Publ
 	if registration.Unregister {
 		s.config.Logger.Info("unregistering client")
 		// We save an empty registration, only keeping version and installation-id
-		emptyRegistration := &protobuf.PushNotificationRegistration{
-			Version:        registration.Version,
-			InstallationId: registration.InstallationId,
-		}
-		if err := s.persistence.SavePushNotificationRegistration(common.HashPublicKey(publicKey), emptyRegistration); err != nil {
+		if err := s.persistence.UnregisterPushNotificationRegistration(common.HashPublicKey(publicKey), registration.InstallationId, registration.Version); err != nil {
 			response.Error = protobuf.PushNotificationRegistrationResponse_INTERNAL_ERROR
 			s.config.Logger.Error("failed to unregister ", zap.Error(err))
 			return response