diff --git a/src/constants.ts b/src/constants.ts
index c81f94a..4bbb7ac 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -7,7 +7,6 @@ const API_MAPPING: Record<string, string> = {
 export const baseUrl = new URL(location.href).origin
 export const apiUrl = API_MAPPING[baseUrl]
 
-export const LEGACY_KEY_FILENAME_FORMAT = 'exporter-format'
 export const KEY_LANGUAGE = 'exporter:language'
 export const KEY_FILENAME_FORMAT = 'exporter:filename_format'
 export const KEY_OFFICIAL_JSON_FORMAT = 'exporter:official_json_format'
diff --git a/src/main.tsx b/src/main.tsx
index d1177ce..cc8047a 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,8 +1,6 @@
 import { render } from 'preact'
 import sentinel from 'sentinel-js'
-import { GM_deleteValue, GM_getValue, GM_setValue } from 'vite-plugin-monkey/dist/client'
 import { fetchConversation, processConversation } from './api'
-import { KEY_FILENAME_FORMAT, LEGACY_KEY_FILENAME_FORMAT } from './constants'
 import { getChatIdFromUrl, getConversationChoice, isSharePage } from './page'
 import { Menu } from './ui/Menu'
 import { onloadSafe } from './utils/utils'
@@ -10,25 +8,6 @@ import { onloadSafe } from './utils/utils'
 import './i18n'
 import './styles/missing-tailwind.css'
 
-/**
- * Migrate legacy filename format
- */
-try {
-    const legacyFormat = GM_getValue?.(LEGACY_KEY_FILENAME_FORMAT, '')
-    const localLegacyFormat = localStorage.getItem(LEGACY_KEY_FILENAME_FORMAT)
-    if (legacyFormat) {
-        GM_deleteValue?.(LEGACY_KEY_FILENAME_FORMAT)
-        GM_setValue?.(KEY_FILENAME_FORMAT, JSON.stringify(legacyFormat))
-    }
-    else if (localLegacyFormat) {
-        localStorage.removeItem(LEGACY_KEY_FILENAME_FORMAT)
-        localStorage.setItem(KEY_FILENAME_FORMAT, JSON.stringify(localLegacyFormat))
-    }
-}
-catch (error) {
-    console.error('Failed to migrate legacy filename format', error)
-}
-
 main()
 
 function main() {