diff --git a/docs/en_US/release_notes_5_4.rst b/docs/en_US/release_notes_5_4.rst
index 3e356e863..ac696a1ff 100644
--- a/docs/en_US/release_notes_5_4.rst
+++ b/docs/en_US/release_notes_5_4.rst
@@ -20,6 +20,7 @@ New features
 Housekeeping
 ************
 
+| `Issue #6225 <https://redmine.postgresql.org/issues/6225>`_ -  Updated Flask-Security-Too to the latest v4.
 
 Bug fixes
 *********
diff --git a/requirements.txt b/requirements.txt
index ebdb1b21e..3ed3f7800 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,7 +29,7 @@ psycopg2==2.8.*
 python-dateutil==2.*
 SQLAlchemy==1.3.*
 itsdangerous<=1.1.0
-Flask-Security-Too==3.*
+Flask-Security-Too==4.*
 bcrypt==3.*
 cryptography==3.*
 sshtunnel==0.*
diff --git a/web/migrations/versions/c465fee44968_.py b/web/migrations/versions/c465fee44968_.py
new file mode 100644
index 000000000..07459675d
--- /dev/null
+++ b/web/migrations/versions/c465fee44968_.py
@@ -0,0 +1,57 @@
+
+"""empty message
+
+Revision ID: c465fee44968
+Revises: d0bc9f32b2b9
+Create Date: 2021-06-04 14:42:12.843116
+
+"""
+from pgadmin.model import db, User
+import uuid
+
+
+# revision identifiers, used by Alembic.
+revision = 'c465fee44968'
+down_revision = 'd0bc9f32b2b9'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    db.engine.execute("ALTER TABLE user RENAME TO user_old")
+
+    db.engine.execute("""
+        CREATE TABLE user (
+            id INTEGER NOT NULL,
+            username VARCHAR(256) NOT NULL,
+            email VARCHAR(256),
+            password VARCHAR(256),
+            active BOOLEAN NOT NULL,
+            confirmed_at DATETIME,
+            masterpass_check VARCHAR(256),
+            auth_source VARCHAR(256) NOT NULL DEFAULT 'internal',
+            fs_uniquifier NOT NULL UNIQUE,
+            PRIMARY KEY (id),
+            UNIQUE (username, auth_source, fs_uniquifier),
+            CHECK (active IN (0, 1))
+        );
+        """)
+
+    user_old = db.engine.execute(
+        'select id, username, email, password, active, '
+        'confirmed_at, masterpass_check, auth_source '
+        'from user_old')
+
+    db.engine.execute(User.__table__.insert(), [
+        {
+            **row,
+            'fs_uniquifier': uuid.uuid4().hex
+        } for row in user_old
+    ])
+
+    db.engine.execute("DROP TABLE user_old")
+
+
+def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
+    pass
diff --git a/web/pgadmin/__init__.py b/web/pgadmin/__init__.py
index 6e395f42f..dfc034c93 100644
--- a/web/pgadmin/__init__.py
+++ b/web/pgadmin/__init__.py
@@ -305,7 +305,7 @@ def create_app(app_name=None):
             if current_user.is_authenticated:
                 user_id = current_user.id
             else:
-                user = user_datastore.get_user(config.DESKTOP_USER)
+                user = user_datastore.find_user(email=config.DESKTOP_USER)
                 if user is not None:
                     user_id = user.id
             user_language = Preferences.raw_value(
@@ -697,7 +697,7 @@ def create_app(app_name=None):
             abort(401)
 
         if not config.SERVER_MODE and not current_user.is_authenticated:
-            user = user_datastore.get_user(config.DESKTOP_USER)
+            user = user_datastore.find_user(email=config.DESKTOP_USER)
             # Throw an error if we failed to find the desktop user, to give
             # the sysadmin a hint. We'll continue to try to login anyway as
             # that'll through a nice 500 error for us.
diff --git a/web/pgadmin/browser/__init__.py b/web/pgadmin/browser/__init__.py
index edbd491e7..d6cf78cac 100644
--- a/web/pgadmin/browser/__init__.py
+++ b/web/pgadmin/browser/__init__.py
@@ -32,7 +32,7 @@ from flask_security.recoverable import reset_password_token_status, \
 from flask_security.signals import reset_password_instructions_sent
 from flask_security.utils import config_value, do_flash, get_url, \
     get_message, slash_url_suffix, login_user, send_mail, logout_user
-from flask_security.views import _security, _commit, _ctx
+from flask_security.views import _security, view_commit, _ctx
 from werkzeug.datastructures import MultiDict
 
 import config
@@ -1144,7 +1144,7 @@ if hasattr(config, 'SECURITY_CHANGEABLE') and config.SECURITY_CHANGEABLE:
                 has_error = True
 
             if request.json is None and not has_error:
-                after_this_request(_commit)
+                after_this_request(view_commit)
                 do_flash(*get_message('PASSWORD_CHANGE'))
 
                 old_key = get_crypt_key()[1]
@@ -1310,7 +1310,7 @@ if hasattr(config, 'SECURITY_RECOVERABLE') and config.SECURITY_RECOVERABLE:
                 has_error = True
 
             if not has_error:
-                after_this_request(_commit)
+                after_this_request(view_commit)
                 do_flash(*get_message('PASSWORD_RESET'))
                 login_user(user)
                 return redirect(get_url(_security.post_reset_view) or
diff --git a/web/pgadmin/model/__init__.py b/web/pgadmin/model/__init__.py
index bd90077b7..3afef96eb 100644
--- a/web/pgadmin/model/__init__.py
+++ b/web/pgadmin/model/__init__.py
@@ -20,6 +20,7 @@ things:
 
 from flask_security import UserMixin, RoleMixin
 from flask_sqlalchemy import SQLAlchemy
+import uuid
 
 ##########################################################################
 #
@@ -29,7 +30,7 @@ from flask_sqlalchemy import SQLAlchemy
 #
 ##########################################################################
 
-SCHEMA_VERSION = 29
+SCHEMA_VERSION = 30
 
 ##########################################################################
 #
@@ -76,6 +77,9 @@ class User(db.Model, UserMixin):
     roles = db.relationship('Role', secondary=roles_users,
                             backref=db.backref('users', lazy='dynamic'))
     auth_source = db.Column(db.String(16), unique=True, nullable=False)
+    # fs_uniquifier is required by flask-security-too >= 4.
+    fs_uniquifier = db.Column(db.String(255), unique=True, nullable=False,
+                              default=(lambda _: uuid.uuid4().hex))
 
 
 class Setting(db.Model):