diff --git a/.github/workflows/ghPages.yml b/.github/workflows/ghPages.yml
index 32a8d64cc..26d247d4a 100644
--- a/.github/workflows/ghPages.yml
+++ b/.github/workflows/ghPages.yml
@@ -3,6 +3,7 @@ on:
   push:
     branches:
       - main
+      - nest
   release:
     types:
       - published
diff --git a/.gitignore b/.gitignore
index ef54d4d3e..7a306e84c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,7 +36,8 @@ lerna-debug.log*
 
 # NotifyBC
 **/*.local.*
-/server/database/data.json
+/server/database/**
+!/server/database/.keep
 /server/certs/**
 !/server/certs/.keep
 tsconfig.build.tsbuildinfo
diff --git a/docs/docs/config/database.md b/docs/docs/config/database.md
index 0f91e9f08..3c99360ec 100644
--- a/docs/docs/config/database.md
+++ b/docs/docs/config/database.md
@@ -4,16 +4,14 @@ permalink: /docs/config-database/
 
 # Database
 
-By default _NotifyBC_ uses in-memory database backed up by file in _/server/database/data.json_ for local and docker deployment and MongoDB for Kubernetes deployment. To use MongoDB for non-Kubernetes deployment, add file _/src/datasources/db.datasource.local.json_ with MongoDB connection information such as following:
+By default _NotifyBC_ uses in-memory database backed up by folder _/server/database/_ for local and docker deployment and MongoDB for Kubernetes deployment. To use MongoDB for non-Kubernetes deployment, add file _/src/datasources/db.datasource.(local|\<env\>).(json|js|ts)_ with MongoDB connection information such as following:
 
-```json
-{
-  "name": "db",
-  "connector": "mongodb",
-  "host": "127.0.0.1",
-  "database": "notifyBC",
-  "port": 27017
-}
+```js
+module.exports = {
+  uri: 'mongodb://127.0.0.1:27017/notifyBC',
+  user: process.env.MONGODB_USER,
+  pass: process.env.MONGODB_PASSWORD,
+};
 ```
 
-See [LoopBack MongoDB data source](https://loopback.io/doc/en/lb4/MongoDB-connector.html#creating-a-mongodb-data-source) for more configurable properties.
+See [Mongoose connection options](https://mongoosejs.com/docs/connections.html#options) for more configurable properties.
diff --git a/docs/docs/miscellaneous/upgrade.md b/docs/docs/miscellaneous/upgrade.md
index 6d783c24a..26d32912b 100644
--- a/docs/docs/miscellaneous/upgrade.md
+++ b/docs/docs/miscellaneous/upgrade.md
@@ -267,11 +267,13 @@ Replace _v4.x.x_ with a v4 release, preferably latest, found in GitHub such as _
 
 ## v4 to v5
 
-1. Update file _src/datasources/db.datasource.(local|<env>).(json|js|ts)_
+v5 introduced following backward incompatible changes that need to be addressed in this order
 
-   1. remove _name_ property
-   2. remove _connector_ property
-   3. rename _url_ property to _uri_
+1. If you use default in-memory database, data in _server/database/data.json_ will not be migrated automatically. Manually migrate if necessary.
+2. Update file _src/datasources/db.datasource.local.json_
+
+   1. rename _url_ property to _uri_
+   2. for other properties, instead of following [LoopBack MongoDB data source](https://loopback.io/doc/en/lb4/MongoDB-connector.html#creating-a-mongodb-data-source), follow [Mongoose connection options](https://mongoosejs.com/docs/connections.html#options)
 
    For example, change
 
@@ -290,3 +292,21 @@ Replace _v4.x.x_ with a v4 release, preferably latest, found in GitHub such as _
      "uri": "mongodb://127.0.0.1:27017/notifyBC"
    }
    ```
+
+After above changes are addressed, upgrading to v5 is as simple as
+
+```sh
+git pull
+git checkout tags/v5.x.x -b <branch_name>
+yarn install && yarn build
+```
+
+or, if _NotifyBC_ is deployed to Kubernetes using Helm.
+
+```sh
+git pull
+git checkout tags/v5.x.x -b <branch_name>
+helm upgrade <release-name> -f helm/platform-specific/<platform>.yaml -f helm/values.local.yaml helm
+```
+
+Replace _v5.x.x_ with a v5 release, preferably latest, found in GitHub such as _v5.0.0_.
diff --git a/helm/templates/configmap.yaml b/helm/templates/configmap.yaml
index 045545c43..1b041c26c 100644
--- a/helm/templates/configmap.yaml
+++ b/helm/templates/configmap.yaml
@@ -53,9 +53,7 @@ data:
     };
   db.datasource.production.js: |-
     module.exports = {
-      name: 'db',
-      connector: 'mongodb',
-      url: `mongodb://${process.env.MONGODB_USER}:${process.env.MONGODB_PASSWORD}@${process.env.DATABASE_SERVICE_NAME}:${process.env.DB_PORT || 27017}/${process.env.MONGODB_DATABASE}?replicaSet=${process.env.MONGODB_REPLICA_SET_NAME}`
+      uri: `mongodb://${process.env.MONGODB_USER}:${process.env.MONGODB_PASSWORD}@${process.env.DATABASE_SERVICE_NAME}:${process.env.DB_PORT || 27017}/${process.env.MONGODB_DATABASE}?replicaSet=${process.env.MONGODB_REPLICA_SET_NAME}`
     };
   {{- range $key, $val := .Values.configMap }}
   {{- $key | nindent 2 }}: |
diff --git a/package.json b/package.json
index bb9016de4..faaefa9d5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "notify-bc",
-  "version": "4.1.9",
+  "version": "5.0.0",
   "dbSchemaVersion": "0.8.0",
   "description": "A versatile notification API server",
   "author": "",
diff --git a/server/database/.keep b/server/database/.keep
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/app.module.ts b/src/app.module.ts
index cbf6f13eb..a5bddf1fe 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -1,13 +1,13 @@
 import { Module } from '@nestjs/common';
-import { AppController } from './app.controller';
-import { AppService } from './app.service';
-import { ConfigModule } from './config/config.module';
+import { MongooseModule } from '@nestjs/mongoose';
+import { AdministratorsModule } from './api/administrators/administrators.module';
+import { BouncesModule } from './api/bounces/bounces.module';
 import { ConfigurationsModule } from './api/configurations/configurations.module';
 import { NotificationsModule } from './api/notifications/notifications.module';
 import { SubscriptionsModule } from './api/subscriptions/subscriptions.module';
-import { AdministratorsModule } from './api/administrators/administrators.module';
-import { BouncesModule } from './api/bounces/bounces.module';
-import { MongooseModule } from '@nestjs/mongoose';
+import { AppController } from './app.controller';
+import { AppService } from './app.service';
+import { ConfigModule } from './config/config.module';
 import { DbConfigService } from './config/db-config.service';
 
 @Module({
@@ -20,8 +20,17 @@ import { DbConfigService } from './config/db-config.service';
     BouncesModule,
     MongooseModule.forRootAsync({
       imports: [ConfigModule],
-      useFactory: async (dbConfigService: DbConfigService) =>
-        dbConfigService.get(),
+      useFactory: async (dbConfigService: DbConfigService) => {
+        const dbConfig = dbConfigService.get();
+        if (dbConfig.uri) return dbConfig;
+        const mongod =
+          await require('mongodb-memory-server').MongoMemoryServer.create({
+            instance: dbConfig,
+          });
+        return {
+          uri: mongod.getUri(),
+        };
+      },
       inject: [DbConfigService],
     }),
   ],
diff --git a/src/config/config.factory.ts b/src/config/config.factory.ts
index caf993b49..2e4048131 100644
--- a/src/config/config.factory.ts
+++ b/src/config/config.factory.ts
@@ -1,7 +1,7 @@
-import * as path from 'path';
-import * as fs from 'fs';
-import { ConfigType } from './constants';
+import fs from 'fs';
 import { isArray, mergeWith } from 'lodash';
+import path from 'path';
+import { ConfigType } from './constants';
 
 const config: Record<ConfigType, any> = {
   [ConfigType.AppConfig]: undefined,
@@ -53,12 +53,12 @@ function init() {
   config[ConfigType.AppConfig] = options;
   config[ConfigType.MiddlewareConfig] = middlewareConfigs;
 
-  let dsFiles: string[] = ['db.datasource.js'];
+  let dsFiles: string[] = ['db.datasource.json', 'db.datasource.js'];
   if (process.env.NODE_ENV) {
-    dsFiles = [
+    dsFiles = dsFiles.concat([
       `db.datasource.${process.env.NODE_ENV}.json`,
       `db.datasource.${process.env.NODE_ENV}.js`,
-    ];
+    ]);
   }
   if (process.env.NODE_ENV !== 'test') {
     dsFiles = dsFiles.concat([
diff --git a/src/datasources/db.datasource.json b/src/datasources/db.datasource.json
new file mode 100644
index 000000000..fefee0e04
--- /dev/null
+++ b/src/datasources/db.datasource.json
@@ -0,0 +1,3 @@
+{
+  "dbPath": "server/database"
+}
diff --git a/src/datasources/db.datasource.ts b/src/datasources/db.datasource.ts
deleted file mode 100644
index 5aeeb4c25..000000000
--- a/src/datasources/db.datasource.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-export default {
-  name: 'db',
-  localStorage: '',
-  file: 'server/database/data.json',
-  connector: 'memory',
-};
diff --git a/tsconfig.json b/tsconfig.json
index f572c2abc..5e429f85d 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -17,6 +17,7 @@
     "strictBindCallApply": false,
     "forceConsistentCasingInFileNames": false,
     "noFallthroughCasesInSwitch": false,
-    "allowJs": true
+    "allowJs": true,
+    "esModuleInterop": true
   }
 }