diff --git a/.blueprint/generate-generator/templates/command.ts.ejs b/.blueprint/generate-generator/templates/command.ts.ejs
index 2dbdefa750df..b014bcbaa807 100644
--- a/.blueprint/generate-generator/templates/command.ts.ejs
+++ b/.blueprint/generate-generator/templates/command.ts.ejs
@@ -18,9 +18,9 @@
  */
 import type { JHipsterCommandDefinition } from '<%- generatorRelativePath %>base/api.js';
 
-const command: JHipsterCommandDefinition = {
+const command = {
   configs: {},
   import: [],
-};
+} as const satisfies JHipsterCommandDefinition;
 
 export default command;
diff --git a/eslint.config.js b/eslint.config.js
index 6d01d6c24ac2..906b9c489982 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -29,6 +29,7 @@ export default ts.config(
     },
     rules: {
       '@typescript-eslint/consistent-type-imports': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/ban-ts-comment': ['off', { 'ts-nocheck': true }],
       '@typescript-eslint/consistent-type-definitions': 'off',
       '@typescript-eslint/no-empty-function': 'off',
diff --git a/generators/angular/generator.ts b/generators/angular/generator.ts
index b3ea7497a819..5e8cd9047611 100644
--- a/generators/angular/generator.ts
+++ b/generators/angular/generator.ts
@@ -234,8 +234,8 @@ export default class AngularGenerator extends BaseApplicationGenerator {
 
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ control }) {
-        control.cleanupFiles({
+      async cleanup({ control }) {
+        await control.cleanupFiles({
           '8.6.1': ['.eslintrc.json', '.eslintignore'],
         });
       },
diff --git a/generators/base-core/generator.ts b/generators/base-core/generator.ts
index b6e8226729b2..f44adcd8fb83 100644
--- a/generators/base-core/generator.ts
+++ b/generators/base-core/generator.ts
@@ -196,7 +196,7 @@ export default class CoreGenerator extends YeomanGenerator<JHipsterGeneratorOpti
         !this.options.reproducibleTests &&
         !this.jhipsterConfig.jhipsterVersion
       ) {
-        this.jhipsterConfig.jhipsterVersion = packageJson.version;
+        this.storeCurrentJHipsterVersion();
       }
     }
 
@@ -234,6 +234,10 @@ export default class CoreGenerator extends YeomanGenerator<JHipsterGeneratorOpti
     return super.usage().replace('yo jhipster:', 'jhipster ');
   }
 
+  storeCurrentJHipsterVersion(): void {
+    this.jhipsterConfig.jhipsterVersion = packageJson.version;
+  }
+
   /**
    * @deprecated
    */
diff --git a/generators/bootstrap/support/eslint-transform.ts b/generators/bootstrap/support/eslint-transform.ts
index 7982f8930012..ed22891e1bb9 100644
--- a/generators/bootstrap/support/eslint-transform.ts
+++ b/generators/bootstrap/support/eslint-transform.ts
@@ -75,8 +75,8 @@ export const createESLintTransform = function (
         this?.log?.warn?.(errorMessage);
       }
     },
-    () => {
-      pool.destroy();
+    async () => {
+      await pool.destroy();
     },
   );
 };
diff --git a/generators/bootstrap/support/java-unused-imports-transform.ts b/generators/bootstrap/support/java-unused-imports-transform.ts
index a3a240b0f7e3..b7c1352e34cf 100644
--- a/generators/bootstrap/support/java-unused-imports-transform.ts
+++ b/generators/bootstrap/support/java-unused-imports-transform.ts
@@ -44,8 +44,8 @@ export const createRemoveUnusedImportsTransform = function (
         }
       }
     },
-    () => {
-      pool.destroy();
+    async () => {
+      await pool.destroy();
     },
   );
 };
diff --git a/generators/bootstrap/support/prettier-support.ts b/generators/bootstrap/support/prettier-support.ts
index 945c97c33e8a..3ff4947130bd 100644
--- a/generators/bootstrap/support/prettier-support.ts
+++ b/generators/bootstrap/support/prettier-support.ts
@@ -92,8 +92,8 @@ export const createPrettierTransform = async function (
         this?.log?.warn?.(errorMessage);
       }
     },
-    () => {
-      pool?.destroy();
+    async () => {
+      await pool?.destroy();
     },
   );
 };
diff --git a/generators/common/generator.ts b/generators/common/generator.ts
index 32c10acbed31..6bda63fd4519 100644
--- a/generators/common/generator.ts
+++ b/generators/common/generator.ts
@@ -196,8 +196,8 @@ export default class CommonGenerator extends BaseApplicationGenerator {
   // Public API method used by the getter and also by Blueprints
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ application, control }) {
-        control.cleanupFiles({
+      async cleanup({ application, control }) {
+        await control.cleanupFiles({
           '7.1.1': [[!application.skipCommitHook, '.huskyrc']],
           '7.6.1': [[application.skipClient, 'npmw', 'npmw.cmd']],
           '8.0.0-rc.2': [[!application.skipCommitHook, '.lintstagedrc.js']],
diff --git a/generators/docker-compose/generator.ts b/generators/docker-compose/generator.ts
index 1d767c02ef2b..3d73977b185e 100644
--- a/generators/docker-compose/generator.ts
+++ b/generators/docker-compose/generator.ts
@@ -135,10 +135,10 @@ export default class DockerComposeGenerator extends BaseWorkspacesGenerator {
 
   get loadingWorkspaces() {
     return {
-      loadBaseDeployment({ deployment }) {
+      async loadBaseDeployment({ deployment }) {
         deployment.jwtSecretKey = this.jhipsterConfig.jwtSecretKey;
 
-        loadDockerDependenciesTask.call(this, { context: deployment });
+        await loadDockerDependenciesTask.call(this, { context: deployment });
       },
       loadPlatformConfig({ deployment }) {
         this.loadDeploymentConfig({ deployment });
diff --git a/generators/generate-blueprint/command.ts b/generators/generate-blueprint/command.ts
index 4d6ae7721a0e..4973b0446df6 100644
--- a/generators/generate-blueprint/command.ts
+++ b/generators/generate-blueprint/command.ts
@@ -31,7 +31,7 @@ import {
   SUB_GENERATORS,
 } from './constants.js';
 
-const command: JHipsterCommandDefinition = {
+const command = {
   configs: {
     recreatePackageLock: {
       description: 'Recreate package lock',
@@ -106,6 +106,6 @@ const command: JHipsterCommandDefinition = {
     },
   },
   import: [GENERATOR_INIT],
-};
+} as const satisfies JHipsterCommandDefinition;
 
 export default command;
diff --git a/generators/generate-blueprint/generator.ts b/generators/generate-blueprint/generator.ts
index 389123b2195c..d2f29cbed949 100644
--- a/generators/generate-blueprint/generator.ts
+++ b/generators/generate-blueprint/generator.ts
@@ -144,6 +144,9 @@ export default class extends BaseGenerator {
 
   get composing() {
     return this.asComposingTaskGroup({
+      storeCurrentVersion() {
+        this.storeCurrentJHipsterVersion();
+      },
       async compose() {
         if (this.jhipsterConfig[LOCAL_BLUEPRINT_OPTION]) return;
         const initGenerator = await this.composeWithJHipster(GENERATOR_INIT, { generatorOptions: { packageJsonType: 'module' } });
@@ -344,7 +347,7 @@ export default class extends BaseGenerator {
 
   get postInstall() {
     return this.asPostInstallTaskGroup({
-      async addSnapshot() {
+      async addSnapshot({ control }) {
         const { [LOCAL_BLUEPRINT_OPTION]: localBlueprint } = this.jhipsterConfig;
         const {
           skipInstall,
@@ -377,6 +380,21 @@ This is a new blueprint, executing '${chalk.yellow('npm run update-snapshot')}'
           }
           this.log.warn('Fail to generate snapshots');
         }
+
+        if (control.jhipsterOldVersion) {
+          // Apply prettier and eslint to fix non generated files on upgrade.
+          try {
+            await this.spawnCommand('npm', ['run', 'prettier-format']);
+          } catch {
+            // Ignore error
+          }
+
+          try {
+            await this.spawnCommand('npm', ['run', 'lint-fix']);
+          } catch {
+            // Ignore error
+          }
+        }
       },
     });
   }
diff --git a/generators/java/generators/openapi-generator/generator.ts b/generators/java/generators/openapi-generator/generator.ts
index b98a3d3c35d8..752d70a9d304 100644
--- a/generators/java/generators/openapi-generator/generator.ts
+++ b/generators/java/generators/openapi-generator/generator.ts
@@ -34,8 +34,8 @@ export default class OpenapiGeneratorGenerator extends BaseApplicationGenerator
 
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ application, control }) {
-        control.cleanupFiles({
+      async cleanup({ application, control }) {
+        await control.cleanupFiles({
           '8.6.1': [[application.buildToolGradle!, 'gradle/swagger.gradle']],
         });
       },
diff --git a/generators/javascript/generators/bootstrap/command.ts b/generators/javascript/generators/bootstrap/command.ts
index 28de8ab124fc..cfdbedb71364 100644
--- a/generators/javascript/generators/bootstrap/command.ts
+++ b/generators/javascript/generators/bootstrap/command.ts
@@ -18,7 +18,7 @@
  */
 import type { JHipsterCommandDefinition } from '../../../../lib/command/index.js';
 
-const command: JHipsterCommandDefinition = {
+const command = {
   configs: {
     packageJsonNodeEngine: {
       cli: {
@@ -39,6 +39,6 @@ const command: JHipsterCommandDefinition = {
     },
   },
   import: [],
-};
+} as const satisfies JHipsterCommandDefinition;
 
 export default command;
diff --git a/generators/javascript/types.d.ts b/generators/javascript/types.d.ts
index ddddcd46d69f..190c9ca53965 100644
--- a/generators/javascript/types.d.ts
+++ b/generators/javascript/types.d.ts
@@ -1,3 +1,8 @@
+import type { ExportApplicationPropertiesFromCommand } from '../../lib/command/types.js';
+import type JavascriptBootstrapCommand from './generators/bootstrap/command.ts';
+
+type JavascriptBootstrapProperties = ExportApplicationPropertiesFromCommand<typeof JavascriptBootstrapCommand>;
+
 export type JavaScriptSourceType = {
   mergePrettierConfig?: (config: Record<string, unknown>) => void;
   addPrettierIgnore?: (newContent: string) => void;
@@ -6,9 +11,8 @@ export type JavaScriptSourceType = {
   addEslintConfig?: (opts: { import?: string | string[]; config?: string | string[] }) => void;
 };
 
-export type JavaScriptApplication = {
+export type JavaScriptApplication = JavascriptBootstrapProperties & {
   packageJsonNodeEngine?: boolean | string;
-  packageJsonType?: string;
   eslintConfigFile?: string;
 
   addPrettierExtensions?: (extensions: string[]) => void;
diff --git a/generators/react/generator.ts b/generators/react/generator.ts
index 24d041e48de8..ebf61fb5a8bc 100644
--- a/generators/react/generator.ts
+++ b/generators/react/generator.ts
@@ -155,8 +155,8 @@ export default class ReactGenerator extends BaseApplicationGenerator {
 
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ control }) {
-        control.cleanupFiles({
+      async cleanup({ control }) {
+        await control.cleanupFiles({
           '8.6.1': ['.eslintrc.json', '.eslintignore'],
         });
       },
diff --git a/generators/spring-boot/cleanup.ts b/generators/spring-boot/cleanup.ts
index 846cdcf7b078..9303515105f3 100644
--- a/generators/spring-boot/cleanup.ts
+++ b/generators/spring-boot/cleanup.ts
@@ -25,7 +25,7 @@ import cleanupOauth2 from './cleanup-oauth2.js';
  * Removes server files that where generated in previous JHipster versions and therefore
  * need to be removed.
  */
-export default asWritingTask(function cleanupTask(this, taskParam) {
+export default asWritingTask(async function cleanupTask(this, taskParam) {
   const { application, control } = taskParam;
   if (application.authenticationTypeOauth2) {
     cleanupOauth2.call(this, taskParam);
@@ -209,7 +209,7 @@ export default asWritingTask(function cleanupTask(this, taskParam) {
     this.removeFile(`${application.javaPackageSrcDir}config/LocaleConfiguration.java`);
   }
 
-  control.cleanupFiles({
+  await control.cleanupFiles({
     '8.6.1': [[application.authenticationTypeOauth2!, `${application.javaPackageSrcDir}security/oauth2/JwtGrantedAuthorityConverter.java`]],
   });
 });
diff --git a/generators/spring-cloud/generators/gateway/generator.ts b/generators/spring-cloud/generators/gateway/generator.ts
index d95dbac395c1..285692171d29 100644
--- a/generators/spring-cloud/generators/gateway/generator.ts
+++ b/generators/spring-cloud/generators/gateway/generator.ts
@@ -70,8 +70,8 @@ export default class GatewayGenerator extends BaseApplicationGenerator {
 
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ control, application }) {
-        control.cleanupFiles({
+      async cleanup({ control, application }) {
+        await control.cleanupFiles({
           '8.6.1': [
             [
               application.reactive && (application as any).serviceDiscoveryAny,
diff --git a/generators/vue/generator.ts b/generators/vue/generator.ts
index e2d65daa2091..8e174c41bdf0 100644
--- a/generators/vue/generator.ts
+++ b/generators/vue/generator.ts
@@ -145,8 +145,8 @@ export default class VueGenerator extends BaseApplicationGenerator {
 
   get writing() {
     return this.asWritingTaskGroup({
-      cleanup({ control }) {
-        control.cleanupFiles({
+      async cleanup({ control }) {
+        await control.cleanupFiles({
           '8.6.1': ['.eslintrc.json', '.eslintignore'],
         });
       },
diff --git a/lib/types/application/options.d.ts b/lib/types/application/options.d.ts
index f65aeab19a61..a089c1ed9a1d 100644
--- a/lib/types/application/options.d.ts
+++ b/lib/types/application/options.d.ts
@@ -9,6 +9,7 @@ export type ApplicationOptions = Simplify<
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/client/command.js').default> &
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/java/generators/bootstrap/command.js').default> &
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/java/generators/build-tool/command.js').default> &
+    ExportGeneratorOptionsFromCommand<typeof import('../../../generators/javascript/generators/bootstrap/command.js').default> &
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/javascript/generators/prettier/command.js').default> &
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/jdl/command.js').default> &
     ExportGeneratorOptionsFromCommand<typeof import('../../../generators/languages/command.js').default> &
diff --git a/lib/types/application/yo-rc.d.ts b/lib/types/application/yo-rc.d.ts
index 9f67e2ee4604..909ba4e572e4 100644
--- a/lib/types/application/yo-rc.d.ts
+++ b/lib/types/application/yo-rc.d.ts
@@ -18,6 +18,7 @@ export type ApplicationConfiguration = Simplify<
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/client/command.js').default> &
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/java/generators/bootstrap/command.js').default> &
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/java/generators/build-tool/command.js').default> &
+    ExportStoragePropertiesFromCommand<typeof import('../../../generators/javascript/generators/bootstrap/command.js').default> &
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/javascript/generators/prettier/command.js').default> &
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/jdl/command.js').default> &
     ExportStoragePropertiesFromCommand<typeof import('../../../generators/languages/command.js').default> &