diff --git a/platform/mv3/extension/js/background.js b/platform/mv3/extension/js/background.js
index 66d17a788..e250d1025 100644
--- a/platform/mv3/extension/js/background.js
+++ b/platform/mv3/extension/js/background.js
@@ -50,6 +50,7 @@ import {
     excludeFromStrictBlock,
     getEnabledRulesetsDetails,
     getRulesetDetails,
+    patchDefaultRulesets,
     setStrictBlockMode,
     updateDynamicRules,
 } from './ruleset-manager.js';
@@ -377,22 +378,24 @@ function onMessage(request, sender, callback) {
 async function start() {
     await loadRulesetConfig();
 
-    // Potentially enable new default rulesets
+    const currentVersion = getCurrentVersion();
+    const isNewVersion = currentVersion !== rulesetConfig.version;
+
+    // The default rulesets may have changed, find out new ruleset to enable,
+    // obsolete ruleset to remove.
+    if ( isNewVersion ) {
+        ubolLog(`Version change: ${rulesetConfig.version} => ${currentVersion}`);
+        rulesetConfig.version = currentVersion;
+        await patchDefaultRulesets();
+        saveRulesetConfig();
+    }
 
     const rulesetsUpdated = process.wakeupRun === false &&
         await enableRulesets(rulesetConfig.enabledRulesets);
 
     // We need to update the regex rules only when ruleset version changes.
-    if ( process.wakeupRun === false ) {
-        const currentVersion = getCurrentVersion();
-        if ( currentVersion !== rulesetConfig.version ) {
-            ubolLog(`Version change: ${rulesetConfig.version} => ${currentVersion}`);
-            rulesetConfig.version = currentVersion;
-            saveRulesetConfig();
-            if ( rulesetsUpdated === false ) {
-                updateDynamicRules();
-            }
-        }
+    if ( isNewVersion && rulesetsUpdated === false ) {
+        updateDynamicRules();
     }
 
     // Permissions may have been removed while the extension was disabled
diff --git a/platform/mv3/extension/js/config.js b/platform/mv3/extension/js/config.js
index e3859e63f..0c79dd62b 100644
--- a/platform/mv3/extension/js/config.js
+++ b/platform/mv3/extension/js/config.js
@@ -24,13 +24,11 @@ import {
     sessionRead, sessionWrite,
 } from './ext.js';
 
-import { defaultRulesetsFromLanguage } from './ruleset-manager.js';
-
 /******************************************************************************/
 
 export const rulesetConfig = {
     version: '',
-    enabledRulesets: [ 'default' ],
+    enabledRulesets: [],
     autoReload: true,
     showBlockedCount: true,
     strictBlockMode: true,
@@ -67,7 +65,6 @@ export async function loadRulesetConfig() {
         sessionWrite('rulesetConfig', rulesetConfig);
         return;
     }
-    rulesetConfig.enabledRulesets = await defaultRulesetsFromLanguage();
     sessionWrite('rulesetConfig', rulesetConfig);
     localWrite('rulesetConfig', rulesetConfig);
     process.firstRun = true;
diff --git a/platform/mv3/extension/js/ruleset-manager.js b/platform/mv3/extension/js/ruleset-manager.js
index c18a575d9..44443bfd5 100644
--- a/platform/mv3/extension/js/ruleset-manager.js
+++ b/platform/mv3/extension/js/ruleset-manager.js
@@ -593,6 +593,40 @@ async function defaultRulesetsFromLanguage() {
 
 /******************************************************************************/
 
+async function patchDefaultRulesets() {
+    const [
+        oldDefaultIds = [],
+        newDefaultIds,
+        newIds,
+    ] = await Promise.all([
+        localRead('defaultRulesetIds'),
+        defaultRulesetsFromLanguage(),
+        getRulesetDetails(),
+    ]);
+    const toAdd = [];
+    const toRemove = [];
+    for ( const id of newDefaultIds ) {
+        if ( oldDefaultIds.includes(id) ) { continue; }
+        toAdd.push(id);
+    }
+    for ( const id of oldDefaultIds ) {
+        if ( newDefaultIds.includes(id) ) { continue; }
+        toRemove.push(id);
+    }
+    for ( const id of rulesetConfig.enabledRulesets ) {
+        if ( newIds.has(id) ) { continue; }
+        toRemove.push(id);
+    }
+    localWrite('defaultRulesetIds', newDefaultIds);
+    if ( toAdd.length === 0 && toRemove.length === 0 ) { return; }
+    const enabledRulesets = new Set(rulesetConfig.enabledRulesets);
+    toAdd.forEach(id => enabledRulesets.add(id));
+    toRemove.forEach(id => enabledRulesets.delete(id));
+    rulesetConfig.enabledRulesets = Array.from(enabledRulesets);
+}
+
+/******************************************************************************/
+
 async function enableRulesets(ids) {
     const afterIds = new Set(ids);
     const [ beforeIds, adminIds, rulesetDetails ] = await Promise.all([
@@ -681,6 +715,7 @@ export {
     filteringModesToDNR,
     getRulesetDetails,
     getEnabledRulesetsDetails,
+    patchDefaultRulesets,
     setStrictBlockMode,
     updateDynamicRules,
 };