diff --git a/aws/s3.go b/aws/s3.go
index 0f44a86d..b632dbeb 100644
--- a/aws/s3.go
+++ b/aws/s3.go
@@ -2,7 +2,6 @@ package aws
 
 import (
 	"context"
-	"encoding/hex"
 	"fmt"
 	"io"
 	"net/http"
@@ -16,7 +15,7 @@ import (
 )
 
 var (
-	AWSS3SumKey = http.CanonicalHeaderKey("x-rqlite-auto-backup-sum")
+	AWSS3IDKey = http.CanonicalHeaderKey("x-rqlite-auto-backup-id")
 )
 
 // S3Config is the subconfig for the S3 storage type
@@ -73,7 +72,7 @@ func (s *S3Client) String() string {
 }
 
 // Upload uploads data to S3.
-func (s *S3Client) Upload(ctx context.Context, reader io.Reader, sum []byte) error {
+func (s *S3Client) Upload(ctx context.Context, reader io.Reader, id string) error {
 	sess, err := s.createSession()
 	if err != nil {
 		return err
@@ -93,9 +92,9 @@ func (s *S3Client) Upload(ctx context.Context, reader io.Reader, sum []byte) err
 		Body:   reader,
 	}
 
-	if sum != nil {
+	if id != "" {
 		input.Metadata = map[string]*string{
-			AWSS3SumKey: aws.String(hex.EncodeToString(sum)),
+			AWSS3IDKey: aws.String(id),
 		}
 	}
 	_, err = uploader.UploadWithContext(ctx, input)
@@ -106,12 +105,11 @@ func (s *S3Client) Upload(ctx context.Context, reader io.Reader, sum []byte) err
 	return nil
 }
 
-// CurrentSum returns the last SHA256 sum uploaded to S3. It is always
-// read from S3 and never cached.
-func (s *S3Client) CurrentSum(ctx context.Context) ([]byte, error) {
+// CurrentID returns the last ID uploaded to S3.
+func (s *S3Client) CurrentID(ctx context.Context) (string, error) {
 	sess, err := s.createSession()
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 
 	svc := s3.New(sess)
@@ -122,14 +120,14 @@ func (s *S3Client) CurrentSum(ctx context.Context) ([]byte, error) {
 
 	result, err := svc.HeadObjectWithContext(ctx, input)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get object head for %v: %w", s, err)
+		return "", fmt.Errorf("failed to get object head for %v: %w", s, err)
 	}
 
-	sumHex, ok := result.Metadata[AWSS3SumKey]
+	id, ok := result.Metadata[AWSS3IDKey]
 	if !ok {
-		return nil, fmt.Errorf("sum metadata not found for %v", s)
+		return "", fmt.Errorf("sum metadata not found for %v", s)
 	}
-	return hex.DecodeString(*sumHex)
+	return *id, nil
 }
 
 // Download downloads data from S3.
diff --git a/aws/s3_test.go b/aws/s3_test.go
index cee1dad5..95b6350c 100644
--- a/aws/s3_test.go
+++ b/aws/s3_test.go
@@ -87,7 +87,7 @@ func TestS3ClientUploadOK(t *testing.T) {
 			if input.Metadata == nil {
 				t.Errorf("expected metadata to be non-nil")
 			}
-			exp, got := "736f6d652d7368613235362d73756d", *input.Metadata[http.CanonicalHeaderKey(AWSS3SumKey)]
+			exp, got := "some-id", *input.Metadata[http.CanonicalHeaderKey(AWSS3IDKey)]
 			if exp != got {
 				t.Errorf("expected metadata to contain %q, got %q", exp, got)
 			}
@@ -106,7 +106,7 @@ func TestS3ClientUploadOK(t *testing.T) {
 	}
 
 	reader := strings.NewReader("test data")
-	err := client.Upload(context.Background(), reader, []byte("some-sha256-sum"))
+	err := client.Upload(context.Background(), reader, "some-id")
 	if err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}
@@ -138,7 +138,7 @@ func TestS3ClientUploadFail(t *testing.T) {
 	}
 
 	reader := strings.NewReader("test data")
-	err := client.Upload(context.Background(), reader, nil)
+	err := client.Upload(context.Background(), reader, "")
 	if err == nil {
 		t.Fatal("Expected error, got nil")
 	}
diff --git a/store/provider.go b/store/provider.go
index 02c19e50..3b1117e9 100644
--- a/store/provider.go
+++ b/store/provider.go
@@ -31,16 +31,16 @@ func NewProvider(s *Store, v, c bool) *Provider {
 	}
 }
 
-// LastModified returns the time the data managed by the Provider was
-// last modified.
-func (p *Provider) LastModified() (time.Time, error) {
+// LastIndex returns the cluster-wide index the data managed by the DataProvider was
+// last modified by.
+func (p *Provider) LastIndex() (uint64, error) {
 	stats.Add(numProviderChecks, 1)
-	return p.str.db.LastModified()
+	return p.str.DBAppliedIndex(), nil
 }
 
 // Provider writes the SQLite database to the given path. If path exists,
 // it will be overwritten.
-func (p *Provider) Provide(w io.Writer) (t time.Time, retErr error) {
+func (p *Provider) Provide(w io.Writer) (retErr error) {
 	stats.Add(numProviderProvides, 1)
 	defer func() {
 		if retErr != nil {
@@ -62,8 +62,8 @@ func (p *Provider) Provide(w io.Writer) (t time.Time, retErr error) {
 		time.Sleep(p.retryInterval)
 		nRetries++
 		if nRetries > p.nRetries {
-			return time.Time{}, err
+			return err
 		}
 	}
-	return p.str.db.LastModified()
+	return nil
 }
diff --git a/store/provider_test.go b/store/provider_test.go
index afe2148d..c112d2ba 100644
--- a/store/provider_test.go
+++ b/store/provider_test.go
@@ -50,7 +50,7 @@ func test_SingleNodeProvide(t *testing.T, vaccuum, compress bool) {
 	defer os.Remove(tmpFd.Name())
 	defer tmpFd.Close()
 	provider := NewProvider(s0, vaccuum, compress)
-	if _, err := provider.Provide(tmpFd); err != nil {
+	if err := provider.Provide(tmpFd); err != nil {
 		t.Fatalf("failed to provide SQLite data: %s", err.Error())
 	}
 
@@ -113,7 +113,7 @@ func Test_SingleNodeProvide(t *testing.T) {
 	})
 }
 
-func Test_SingleNodeProvideLastModified(t *testing.T) {
+func Test_SingleNodeProvideLastIndex(t *testing.T) {
 	s, ln := mustNewStore(t)
 	defer ln.Close()
 
@@ -132,7 +132,7 @@ func Test_SingleNodeProvideLastModified(t *testing.T) {
 	defer os.Remove(tmpFile)
 	provider := NewProvider(s, false, false)
 
-	lm, err := provider.LastModified()
+	lm, err := provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
@@ -149,14 +149,14 @@ func Test_SingleNodeProvideLastModified(t *testing.T) {
 		t.Fatalf("failed to wait for FSM to apply")
 	}
 
-	newLM, err := provider.LastModified()
+	newLI, err := provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
-	if !newLM.After(lm) {
-		t.Fatalf("last modified time should have changed")
+	if newLI <= lm {
+		t.Fatalf("last index should have changed")
 	}
-	lm = newLM
+	lm = newLI
 
 	// Try various queries and commands which should not change the database.
 	qr := queryRequestFromString("SELECT * FROM foo", false, false)
@@ -168,26 +168,26 @@ func Test_SingleNodeProvideLastModified(t *testing.T) {
 	if _, err := s.WaitForAppliedFSM(2 * time.Second); err != nil {
 		t.Fatalf("failed to wait for FSM to apply")
 	}
-	newLM, err = provider.LastModified()
+	newLI, err = provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
-	if !newLM.Equal(lm) {
-		t.Fatalf("last modified time should not have changed")
+	if newLI != lm {
+		t.Fatalf("last index should not have changed")
 	}
-	lm = newLM
+	lm = newLI
 
 	if af, err := s.Noop("don't care"); err != nil || af.Error() != nil {
 		t.Fatalf("failed to execute Noop")
 	}
-	newLM, err = provider.LastModified()
+	newLI, err = provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
-	if !newLM.Equal(lm) {
-		t.Fatalf("last modified time should not have changed")
+	if newLI != lm {
+		t.Fatalf("last index should not have changed")
 	}
-	lm = newLM
+	lm = newLI
 
 	er = executeRequestFromStrings([]string{
 		`INSERT INTO foo(id, name) VALUES(1, "fiona")`, // Constraint violation.
@@ -196,14 +196,14 @@ func Test_SingleNodeProvideLastModified(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed to execute on single node: %s", err.Error())
 	}
-	newLM, err = provider.LastModified()
+	newLI, err = provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
-	if !newLM.Equal(lm) {
-		t.Fatalf("last modified time should not have changed with constraint violation")
+	if newLI != lm {
+		t.Fatalf("last index should not have changed with constraint violation")
 	}
-	lm = newLM
+	lm = newLI
 
 	// This should change the database.
 	er = executeRequestFromStrings([]string{
@@ -216,12 +216,12 @@ func Test_SingleNodeProvideLastModified(t *testing.T) {
 	if _, err := s.WaitForAppliedFSM(2 * time.Second); err != nil {
 		t.Fatalf("failed to wait for FSM to apply")
 	}
-	newLM, err = provider.LastModified()
+	newLI, err = provider.LastIndex()
 	if err != nil {
 		t.Fatalf("failed to get last modified: %s", err.Error())
 	}
-	if !newLM.After(lm) {
-		t.Fatalf("last modified time should have changed")
+	if newLI <= lm {
+		t.Fatalf("last index should have changed")
 	}
 }