diff --git a/changelog.md b/changelog.md
index ca2dde7..4bfa840 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 2025-12-16 - 2.13.1 - fix(npmextra)
+merge old npmextra keys into new keys during migration, preserving existing new values
+
+- Changed migration logic to merge data when both old and new keys exist instead of skipping the merge.
+- Merge preserves existing new-key values (old values do not overwrite new ones) and still deletes the old key after migration.
+- Applied the fix in both ts/mod_format/format.npmextra.ts and ts/mod_format/formatters/npmextra.formatter.ts.
+- Adds a console log for successful migrations; behavior for single-key rename remains unchanged.
+
 ## 2025-12-16 - 2.13.0 - feat(tests)
 feat(tests): add sandbox test fixture, CI and editor configs; bump deps
 
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index 3a8b4b6..0034810 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@git.zone/cli',
-  version: '2.13.0',
+  version: '2.13.1',
   description: 'A comprehensive CLI tool for enhancing and managing local development workflows with gitzone utilities, focusing on project setup, version control, code formatting, and template management.'
 }
diff --git a/ts/mod_format/format.npmextra.ts b/ts/mod_format/format.npmextra.ts
index 1f3080c..25423ef 100644
--- a/ts/mod_format/format.npmextra.ts
+++ b/ts/mod_format/format.npmextra.ts
@@ -16,8 +16,17 @@ const migrateNamespaceKeys = (npmextraJson: any): boolean => {
     { oldKey: 'szci', newKey: '@ship.zone/szci' },
   ];
   for (const { oldKey, newKey } of migrations) {
-    if (npmextraJson[oldKey] && !npmextraJson[newKey]) {
-      npmextraJson[newKey] = npmextraJson[oldKey];
+    if (npmextraJson[oldKey]) {
+      if (!npmextraJson[newKey]) {
+        // New key doesn't exist - simple rename
+        npmextraJson[newKey] = npmextraJson[oldKey];
+      } else {
+        // New key exists - merge old into new (old values don't overwrite new)
+        npmextraJson[newKey] = {
+          ...npmextraJson[oldKey],
+          ...npmextraJson[newKey],
+        };
+      }
       delete npmextraJson[oldKey];
       migrated = true;
       console.log(`Migrated npmextra.json: ${oldKey} -> ${newKey}`);
diff --git a/ts/mod_format/formatters/npmextra.formatter.ts b/ts/mod_format/formatters/npmextra.formatter.ts
index c818f7b..9a5e98f 100644
--- a/ts/mod_format/formatters/npmextra.formatter.ts
+++ b/ts/mod_format/formatters/npmextra.formatter.ts
@@ -16,8 +16,17 @@ const migrateNamespaceKeys = (npmextraJson: any): boolean => {
     { oldKey: 'szci', newKey: '@ship.zone/szci' },
   ];
   for (const { oldKey, newKey } of migrations) {
-    if (npmextraJson[oldKey] && !npmextraJson[newKey]) {
-      npmextraJson[newKey] = npmextraJson[oldKey];
+    if (npmextraJson[oldKey]) {
+      if (!npmextraJson[newKey]) {
+        // New key doesn't exist - simple rename
+        npmextraJson[newKey] = npmextraJson[oldKey];
+      } else {
+        // New key exists - merge old into new (old values don't overwrite new)
+        npmextraJson[newKey] = {
+          ...npmextraJson[oldKey],
+          ...npmextraJson[newKey],
+        };
+      }
       delete npmextraJson[oldKey];
       migrated = true;
     }