diff --git a/customiser.py b/customiser.py
index 8eb3bc5..ac69400 100755
--- a/customiser.py
+++ b/customiser.py
@@ -126,7 +126,8 @@ try:
                 f' ...linking to {os.path.join(".", "resources", "user.css")}')
             with open(os.path.join(__dirname__, 'resources', 'preload.js'), 'r', encoding='UTF-8') as insert:
                 append.write(insert.read().replace(
-                    '☃☃☃resources☃☃☃', os.path.join(enhancer_folder, 'resources').replace('\\', '/')))
+                    '☃☃☃resources☃☃☃', os.path.join(enhancer_folder, 'resources').replace('\\', '/'))
+                    .replace('☃☃☃version☃☃☃', enhancer_version))
     else:
         print(
             f' * {os.path.join(filepath, "app","renderer","preload.js")} was not found: step skipped.')
diff --git a/resources/preload.js b/resources/preload.js
index 7d92897..5e9e12b 100644
--- a/resources/preload.js
+++ b/resources/preload.js
@@ -167,9 +167,40 @@ require('electron').remote.getGlobal('setTimeout')(() => {
           el.outerHTML = `<span>${el.getAttribute('alt')}</span>`;
         });
       });
-      observer.observe(document, { childList: true, subtree: true });
+      observer.observe(document, {
+        childList: true,
+        subtree: true,
+      });
     }
 
+    /* update checker */
+    fetch(
+      `https://api.github.com/repos/dragonwocky/notion-enhancer/releases/latest`
+    )
+      .then((res) => res.json())
+      .then((res) => {
+        const local_version = '☃☃☃version☃☃☃'.split('~')[0],
+          repo_version = res.tag_name.slice(1);
+        // compare func from https://github.com/substack/semver-compare
+        if (
+          local_version != repo_version &&
+          [local_version, repo_version].sort((a, b) => {
+            var pa = a.split('.');
+            var pb = b.split('.');
+            for (var i = 0; i < 3; i++) {
+              var na = Number(pa[i]);
+              var nb = Number(pb[i]);
+              if (na > nb) return 1;
+              if (nb > na) return -1;
+              if (!isNaN(na) && isNaN(nb)) return 1;
+              if (isNaN(na) && !isNaN(nb)) return -1;
+            }
+            return 0;
+          })[0] == local_version
+        )
+          alert('notion-enhancer update available!');
+      });
+
     /* hotkey: reload window */
     document.defaultView.addEventListener(
       'keyup',