diff --git a/default.hbs b/default.hbs
index 7a50ce0..1bfd0a8 100644
--- a/default.hbs
+++ b/default.hbs
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="{{@site.lang}}">
+<html lang="{{@site.locale}}">
 
 <head>
   <meta charset="utf-8" />
diff --git a/package.json b/package.json
index 7cf2c73..77c20cc 100644
--- a/package.json
+++ b/package.json
@@ -3,7 +3,7 @@
   "description": "nanao.moe's blog theme",
   "version": "v3.99.0-nanaomoe",
   "engines": {
-    "ghost-api": "v3"
+    "ghost-api": "v4"
   },
   "license": "MIT",
   "author": {
diff --git a/post.hbs b/post.hbs
index b029799..2bf01e8 100644
--- a/post.hbs
+++ b/post.hbs
@@ -24,7 +24,7 @@
             {{#foreach authors}}
             {{#if profile_image}}
             <a href="{{url}}">
-              <img class="post-header__author-image" src="{{img_url profile_image size="xs"}}" alt="{{name}}" />
+              <img class="post-header__author-image" src="{{img_url profile_image size=" xs"}}" alt="{{name}}" />
             </a>
             {{/if}}
             {{/foreach}}
@@ -34,12 +34,19 @@
             Multiple authors
             {{else}}
             {{#foreach authors}}
-              <a href="{{url}}" title="{{name}}" class="post-header__author-name">{{name}}</a>
+            <a href="{{url}}" title="{{name}}" class="post-header__author-name">{{name}}</a>
             {{/foreach}}
             {{/has}}
           </div>
         </div>
         {{/if}}
+        {{#if feature_image_caption}}
+        <p class="post-header__caption">
+          <span class="post-header__caption-text">
+            {{feature_image_caption}}
+          </span>
+        </p>
+        {{/if}}
       </div>
     </div>
   </div>
