diff --git a/packages/core/strapi/lib/Strapi.js b/packages/core/strapi/lib/Strapi.js
index cf80f0329a..cc334fb786 100644
--- a/packages/core/strapi/lib/Strapi.js
+++ b/packages/core/strapi/lib/Strapi.js
@@ -345,15 +345,16 @@ class Strapi {
 
     // Init core store
 
+    await this.runLifecyclesFunctions(LIFECYCLES.REGISTER);
+
+    // TODO: i18N must have added the new fileds before we init the DB
+
     const contentTypes = [
       // todo: move corestore and webhook to real models instead of content types to avoid adding extra attributes
       coreStoreModel,
       webhookModel,
-      ...Object.values(strapi.models),
+      ...Object.values(strapi.contentTypes),
       ...Object.values(strapi.components),
-      ...Object.values(strapi.admin.models),
-      ...Object.values(strapi.plugins).flatMap(plugin => Object.values(plugin.models)),
-      ...Object.values(strapi.api).flatMap(api => Object.values(api.models)),
     ];
 
     // TODO: create in RootProvider
@@ -364,9 +365,6 @@ class Strapi {
 
     await this.db.schema.sync();
 
-    await this.runLifecyclesFunctions(LIFECYCLES.REGISTER);
-    // await this.db.initialize();
-
     this.store = createCoreStore({
       environment: this.config.environment,
       db: this.db,
diff --git a/packages/plugins/i18n/config/functions/register.js b/packages/plugins/i18n/config/functions/register.js
index 08e42d08c1..c7f00b44fb 100644
--- a/packages/plugins/i18n/config/functions/register.js
+++ b/packages/plugins/i18n/config/functions/register.js
@@ -23,8 +23,10 @@ module.exports = () => {
         private: false,
         configurable: false,
         visible: false,
-        collection: modelName,
-        populate: ['_id', 'id', 'locale', PUBLISHED_AT_ATTRIBUTE],
+        type: 'relation',
+        relation: 'oneToMany',
+        target: contentType.uid,
+        // populate: ['_id', 'id', 'locale', PUBLISHED_AT_ATTRIBUTE],
       });
 
       _.set(attributes, 'locale', {
diff --git a/packages/plugins/i18n/config/policies/validateLocaleCreation.js b/packages/plugins/i18n/config/policies/validateLocaleCreation.js
index 2ea19b57bf..11dc773a1b 100644
--- a/packages/plugins/i18n/config/policies/validateLocaleCreation.js
+++ b/packages/plugins/i18n/config/policies/validateLocaleCreation.js
@@ -37,10 +37,10 @@ const validateLocaleCreation = async (ctx, next) => {
 
   if (modelDef.kind === 'singleType') {
     const entity = await strapi.entityService.find(modelDef.uid, {
-      params: { _locale: entityLocale },
+      params: { locale: entityLocale },
     });
 
-    ctx.request.query._locale = body.locale;
+    ctx.request.query.locale = body.locale;
 
     // updating
     if (entity) {
diff --git a/packages/plugins/i18n/controllers/content-types.js b/packages/plugins/i18n/controllers/content-types.js
index efdfd488b1..1a15d9d31f 100644
--- a/packages/plugins/i18n/controllers/content-types.js
+++ b/packages/plugins/i18n/controllers/content-types.js
@@ -33,16 +33,22 @@ module.exports = {
 
     let params = modelDef.kind === 'singleType' ? {} : { id };
 
-    const entity = await strapi.query(model).findOne(params);
+    const entity = await strapi
+      .query(model)
+      .findOne({ where: params, populate: ['localizations'] });
 
     if (!entity) {
       return ctx.notFound();
     }
 
-    const permissions = await strapi.admin.services.permission.find({
-      action_in: [READ_ACTION, CREATE_ACTION],
-      subject: model,
-      role_in: user.roles.map(prop('id')),
+    const permissions = await strapi.admin.services.permission.findMany({
+      where: {
+        action: [READ_ACTION, CREATE_ACTION],
+        subject: model,
+        role: {
+          id: user.roles.map(prop('id')),
+        },
+      },
     });
 
     const localePermissions = permissions
diff --git a/packages/plugins/i18n/services/__tests__/entity-service-decorator.test.js b/packages/plugins/i18n/services/__tests__/entity-service-decorator.test.js
index a749cc9fb5..53aec17c81 100644
--- a/packages/plugins/i18n/services/__tests__/entity-service-decorator.test.js
+++ b/packages/plugins/i18n/services/__tests__/entity-service-decorator.test.js
@@ -152,7 +152,7 @@ describe('Entity service decorator', () => {
 
       const input = {
         params: {
-          _locale: 'fr',
+          locale: 'fr',
         },
         populate: ['test'],
       };
diff --git a/packages/plugins/i18n/services/content-types.js b/packages/plugins/i18n/services/content-types.js
index e0cb87803a..d933f0fd52 100644
--- a/packages/plugins/i18n/services/content-types.js
+++ b/packages/plugins/i18n/services/content-types.js
@@ -54,9 +54,11 @@ const getAndValidateRelatedEntity = async (relatedEntityId, model, locale) => {
   let relatedEntity;
 
   if (kind === 'singleType') {
-    relatedEntity = await strapi.query(model).findOne({});
+    relatedEntity = await strapi.query(model).findOne({ populate: ['localizations'] });
   } else if (relatedEntityId) {
-    relatedEntity = await strapi.query(model).findOne({ id: relatedEntityId });
+    relatedEntity = await strapi
+      .query(model)
+      .findOne({ where: { id: relatedEntityId }, populate: ['localizations'] });
   }
 
   if (relatedEntityId && !relatedEntity) {
diff --git a/packages/plugins/i18n/services/core-api.js b/packages/plugins/i18n/services/core-api.js
index ab6dbbdc43..c6eb6e5775 100644
--- a/packages/plugins/i18n/services/core-api.js
+++ b/packages/plugins/i18n/services/core-api.js
@@ -142,7 +142,7 @@ const createLocalizationHandler = contentType => {
 
   if (isSingleType(contentType)) {
     return async function(ctx) {
-      const entry = await strapi.query(contentType.uid).findOne();
+      const entry = await strapi.query(contentType.uid).findOne({ populate: ['localizations'] });
 
       if (!entry) {
         throw strapi.errors.notFound('baseEntryId.invalid');
@@ -155,7 +155,9 @@ const createLocalizationHandler = contentType => {
   return async function(ctx) {
     const { id: baseEntryId } = ctx.params;
 
-    const entry = await strapi.query(contentType.uid).findOne({ id: baseEntryId });
+    const entry = await strapi
+      .query(contentType.uid)
+      .findOne({ where: { id: baseEntryId }, populate: ['localizations'] });
 
     if (!entry) {
       throw strapi.errors.notFound('baseEntryId.invalid');
diff --git a/packages/plugins/i18n/services/entity-service-decorator.js b/packages/plugins/i18n/services/entity-service-decorator.js
index eade307677..75b6d5bcc5 100644
--- a/packages/plugins/i18n/services/entity-service-decorator.js
+++ b/packages/plugins/i18n/services/entity-service-decorator.js
@@ -5,20 +5,19 @@ const { getService } = require('../utils');
 
 const { syncLocalizations, syncNonLocalizedAttributes } = require('./localizations');
 
-const LOCALE_QUERY_FILTER = '_locale';
+const LOCALE_QUERY_FILTER = 'locale';
 const SINGLE_ENTRY_ACTIONS = ['findOne', 'update', 'delete'];
 const BULK_ACTIONS = ['delete'];
 
 const paramsContain = (key, params) => {
   return (
-    has(key, params) ||
-    has(key, params._where) ||
-    (isArray(params._where) && params._where.some(clause => has(key, clause)))
+    has(key, params.filters) ||
+    (isArray(params.filters) && params.filters.some(clause => has(key, clause)))
   );
 };
 
 /**
- * Adds default locale or replaces _locale by locale in query params
+ * Adds default locale or replaces locale by locale in query params
  * @param {object} params - query params
  */
 // TODO: fix
@@ -32,12 +31,14 @@ const wrapParams = async (params = {}, ctx = {}) => {
 
     return {
       ...omit(LOCALE_QUERY_FILTER, params),
-      locale: params[LOCALE_QUERY_FILTER],
+      filters: {
+        $and: [params.filters || {}, { locale: params[LOCALE_QUERY_FILTER] }],
+      },
     };
   }
 
   const entityDefinedById = paramsContain('id', params) && SINGLE_ENTRY_ACTIONS.includes(action);
-  const entitiesDefinedByIds = paramsContain('id_in', params) && BULK_ACTIONS.includes(action);
+  const entitiesDefinedByIds = paramsContain('id.$in', params) && BULK_ACTIONS.includes(action);
 
   if (entityDefinedById || entitiesDefinedByIds) {
     return params;
@@ -47,7 +48,9 @@ const wrapParams = async (params = {}, ctx = {}) => {
 
   return {
     ...params,
-    locale: await getDefaultLocale(),
+    filters: {
+      $and: [params.filters || {}, { locale: await getDefaultLocale() }],
+    },
   };
 };
 
diff --git a/packages/plugins/i18n/services/localizations.js b/packages/plugins/i18n/services/localizations.js
index 3ff294e997..0f770df7e7 100644
--- a/packages/plugins/i18n/services/localizations.js
+++ b/packages/plugins/i18n/services/localizations.js
@@ -29,7 +29,7 @@ const syncLocalizations = async (entry, { model }) => {
     const updateLocalization = id => {
       const localizations = newLocalizations.filter(localizationId => localizationId !== id);
 
-      return strapi.query(model.uid).update({ id }, { localizations });
+      return strapi.query(model.uid).update({ where: { id }, data: { localizations } });
     };
 
     await Promise.all(entry.localizations.map(({ id }) => updateLocalization(id)));
@@ -52,7 +52,9 @@ const syncNonLocalizedAttributes = async (entry, { model }) => {
       return;
     }
 
-    const updateLocalization = id => strapi.query(model.uid).update({ id }, nonLocalizedAttributes);
+    const updateLocalization = id => {
+      return strapi.query(model.uid).update({ where: { id }, data: nonLocalizedAttributes });
+    };
 
     await Promise.all(entry.localizations.map(({ id }) => updateLocalization(id)));
   }
diff --git a/packages/plugins/i18n/services/permissions/actions.js b/packages/plugins/i18n/services/permissions/actions.js
index a3569e2d31..f05a6a2b72 100644
--- a/packages/plugins/i18n/services/permissions/actions.js
+++ b/packages/plugins/i18n/services/permissions/actions.js
@@ -82,9 +82,12 @@ const syncSuperAdminPermissionsWithLocales = async () => {
     return;
   }
 
-  // TODO: fix
-  const superAdminPermissions = await permissionService.findUserPermissions({
-    roles: [superAdminRole],
+  const superAdminPermissions = await permissionService.findMany({
+    where: {
+      role: {
+        id: superAdminRole.id,
+      },
+    },
   });
 
   const newSuperAdminPermissions = await addAllLocalesToPermissions(superAdminPermissions);
diff --git a/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js b/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
index 2e2c3e1fa5..da835f65a5 100644
--- a/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
+++ b/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
@@ -111,7 +111,7 @@ describe('i18n - Relation-list route', () => {
     const res = await rq({
       method: 'POST',
       url: '/content-manager/relations/application::shop.shop/products',
-      qs: { _locale: 'it' },
+      qs: { locale: 'it' },
     });
 
     expect(res.body).toHaveLength(1);
diff --git a/packages/plugins/i18n/tests/graphql.test.e2e.js b/packages/plugins/i18n/tests/graphql.test.e2e.js
index f04fa59a77..610bffb248 100644
--- a/packages/plugins/i18n/tests/graphql.test.e2e.js
+++ b/packages/plugins/i18n/tests/graphql.test.e2e.js
@@ -51,7 +51,7 @@ describe('Test Graphql API create localization', () => {
 
   afterAll(async () => {
     await strapi.query('plugins::i18n.locale').delete({ where: { id: localeId } });
-    await strapi.query('recipes').deleteMany();
+    await strapi.query('application::recipes.recipes').deleteMany();
     await strapi.destroy();
     await builder.cleanup();
   });
diff --git a/packages/plugins/i18n/tests/locales.test.e2e.js b/packages/plugins/i18n/tests/locales.test.e2e.js
index 8d6fdfa948..5fd71cb77b 100644
--- a/packages/plugins/i18n/tests/locales.test.e2e.js
+++ b/packages/plugins/i18n/tests/locales.test.e2e.js
@@ -365,7 +365,7 @@ describe('CRUD locales', () => {
       } = await rq({
         url: '/content-manager/collection-types/application::product.product',
         method: 'GET',
-        qs: { _locale: 'fr-FR' },
+        qs: { locale: 'fr-FR' },
       });
 
       expect(createdProducts).toHaveLength(1);
@@ -381,7 +381,7 @@ describe('CRUD locales', () => {
       } = await rq({
         url: '/content-manager/collection-types/application::product.product',
         method: 'GET',
-        qs: { _locale: 'fr-FR' },
+        qs: { locale: 'fr-FR' },
       });
       expect(frenchProducts).toHaveLength(0);
 
@@ -390,7 +390,7 @@ describe('CRUD locales', () => {
       } = await rq({
         url: '/content-manager/collection-types/application::product.product',
         method: 'GET',
-        qs: { _locale: 'en' },
+        qs: { locale: 'en' },
       });
       expect(englishProducts).toHaveLength(1);