diff --git a/service/updates/index.go b/service/updates/index.go
index d98d92d7..13285f9d 100644
--- a/service/updates/index.go
+++ b/service/updates/index.go
@@ -118,6 +118,14 @@ type Index struct {
 	Artifacts []*Artifact `json:"Artifacts"`
 
 	versionNum *semver.Version
+
+	// isLocallyGenerated indicates whether the index was generated from a local directory.
+	//
+	// When true:
+	//   - The `Published` field represents the generation time, not a formal release date.
+	//     This timestamp should be ignored when checking for online updates.
+	//   - Downgrades from this locally generated version to an online index should be prevented.
+	isLocallyGenerated bool
 }
 
 // LoadIndex loads and parses an index from the given filename.
@@ -235,6 +243,15 @@ func (index *Index) ShouldUpgradeTo(newIndex *Index) error {
 	case index.Name != newIndex.Name:
 		return errors.New("new index name does not match")
 
+	case index.isLocallyGenerated:
+		if newIndex.versionNum.GreaterThan(index.versionNum) {
+			// Upgrade! (from a locally generated index to an online index)
+			return nil
+		} else {
+			// "Do nothing".
+			return ErrSameIndex
+		}
+
 	case index.Published.After(newIndex.Published):
 		return errors.New("new index is older (time)")
 
diff --git a/service/updates/index_scan.go b/service/updates/index_scan.go
index 1dc1a7f6..3ac52f5f 100644
--- a/service/updates/index_scan.go
+++ b/service/updates/index_scan.go
@@ -234,10 +234,11 @@ func GenerateIndexFromDir(sourceDir string, cfg IndexScanConfig) (*Index, error)
 
 	// Create base index.
 	index := &Index{
-		Name:       cfg.Name,
-		Version:    cfg.Version,
-		Published:  time.Now(),
-		versionNum: indexVersion,
+		Name:               cfg.Name,
+		Version:            cfg.Version,
+		Published:          time.Now(),
+		versionNum:         indexVersion,
+		isLocallyGenerated: true,
 	}
 	if index.Version == "" && cfg.PrimaryArtifact != "" {
 		pv, ok := artifacts[cfg.PrimaryArtifact]