diff --git a/packages/client/src/init.ts b/packages/client/src/init.ts
index dea59ba5b2..9a0b6e3818 100644
--- a/packages/client/src/init.ts
+++ b/packages/client/src/init.ts
@@ -54,6 +54,7 @@ import { reloadChannel } from "@/scripts/unison-reload";
 import { ColdDeviceStorage, defaultStore } from "@/store";
 import { useStream, isReloading } from "@/stream";
 import widgets from "@/widgets";
+import { compareFirefishVersions } from "@/scripts/compare-versions";
 
 function checkForSplash() {
 	const splash = document.getElementById("splash");
@@ -250,23 +251,11 @@ function checkForSplash() {
 		// テーマリビルドするため
 		localStorage.removeItem("theme");
 
-		const isUpdated = (prevVersion: string, currentVersion: string) => {
-			const p = prevVersion.split("-");
-			const c = currentVersion.split("-");
-
-			if (p[0] < c[0]) return true;
-			if (p[0] === c[0] && p[1] == null && c[1] != null) return true;
-			if (p[0] === c[0] && p[1] != null && c[1] != null && p[1] < c[1])
-				return true;
-
-			return false;
-		};
-
 		try {
 			// 変なバージョン文字列来るとcompareVersionsでエラーになるため
 			if (
 				lastVersion != null &&
-				isUpdated(lastVersion, version) &&
+				compareFirefishVersions(lastVersion, version) === 1 &&
 				defaultStore.state.showUpdates
 			) {
 				// ログインしてる場合だけ
diff --git a/packages/client/src/pages/admin/index.vue b/packages/client/src/pages/admin/index.vue
index 1dd8540414..29c43946f3 100644
--- a/packages/client/src/pages/admin/index.vue
+++ b/packages/client/src/pages/admin/index.vue
@@ -85,6 +85,7 @@ import {
 	provideMetadataReceiver,
 } from "@/scripts/page-metadata";
 import icon from "@/scripts/icon";
+import { compareFirefishVersions } from "@/scripts/compare-versions";
 
 const isEmpty = (x: string | null) => x == null || x === "";
 const el = ref<HTMLElement | null>(null);
@@ -121,11 +122,8 @@ os.api("admin/abuse-user-reports", {
 
 if (defaultStore.state.showAdminUpdates) {
 	os.api("latest-version").then((res) => {
-		const cleanRes = parseInt(res?.latest_version.replace(/[^0-9]/g, ""));
-		const cleanVersion = parseInt(version.replace(/[^0-9]/g, ""));
-		if (cleanRes > cleanVersion) {
-			updateAvailable.value = true;
-		}
+		updateAvailable.value =
+			compareFirefishVersions(version, res?.latest_version) === 1;
 	});
 }
 
diff --git a/packages/client/src/scripts/compare-versions.ts b/packages/client/src/scripts/compare-versions.ts
new file mode 100644
index 0000000000..7b232db838
--- /dev/null
+++ b/packages/client/src/scripts/compare-versions.ts
@@ -0,0 +1,19 @@
+const less = -1;
+const same = 0;
+const more = 1;
+
+export const compareFirefishVersions = (
+	oldVersion: string,
+	newVersion: string,
+) => {
+	if (oldVersion === newVersion) return same;
+
+	const o = oldVersion.split("-");
+	const n = newVersion.split("-");
+
+	if (o[0] < n[0]) return more;
+	if (o[0] === n[0] && o[1] == null && n[1] != null) return more;
+	if (o[0] === n[0] && o[1] != null && n[1] != null && o[1] < n[1]) return more;
+
+	return less;
+};
diff --git a/packages/client/src/ui/_common_/navbar.vue b/packages/client/src/ui/_common_/navbar.vue
index b629ddb85f..178eb630f9 100644
--- a/packages/client/src/ui/_common_/navbar.vue
+++ b/packages/client/src/ui/_common_/navbar.vue
@@ -168,6 +168,7 @@ import { i18n } from "@/i18n";
 import { instance } from "@/instance";
 import { version } from "@/config";
 import icon from "@/scripts/icon";
+import { compareFirefishVersions } from "@/scripts/compare-versions";
 
 const isEmpty = (x: string | null) => x == null || x === "";
 
@@ -217,11 +218,8 @@ if (isAdmin) {
 
 if (defaultStore.state.showAdminUpdates) {
 	os.api("latest-version").then((res) => {
-		const cleanRes = parseInt(res?.latest_version.replace(/[^0-9]/g, ""));
-		const cleanVersion = parseInt(version.replace(/[^0-9]/g, ""));
-		if (cleanRes > cleanVersion) {
-			updateAvailable.value = true;
-		}
+		updateAvailable.value =
+			compareFirefishVersions(version, res?.latest_version) === 1;
 	});
 }