diff --git a/physionet-django/notification/utility.py b/physionet-django/notification/utility.py
index 9e03c6d90a..96443031fb 100644
--- a/physionet-django/notification/utility.py
+++ b/physionet-django/notification/utility.py
@@ -1025,3 +1025,19 @@ def notify_event_participant_application(request, user, registered_user, event):
     body = loader.render_to_string('events/email/event_registration.html', context)
     # Not resend the email if there was an integrity error
     send_mail(subject, body, settings.DEFAULT_FROM_EMAIL, [user.email], fail_silently=False)
+
+
+def notify_users_of_training_expiry(user, training, expiry):
+    """
+    Send the training expiry email.
+    """
+
+    subject = f"{settings.SITE_NAME} Training Validation Notification"
+    context = {
+        'name': user.get_full_name(),
+        'SITE_NAME': settings.SITE_NAME,
+        'training': training,
+        'expiry': expiry
+    }
+    body = loader.render_to_string('training/email/training_notification.html', context)
+    send_mail(subject, body, settings.DEFAULT_FROM_EMAIL, [user, ], fail_silently=False)
diff --git a/physionet-django/training/serializers.py b/physionet-django/training/serializers.py
new file mode 100644
index 0000000000..61e10cd0c7
--- /dev/null
+++ b/physionet-django/training/serializers.py
@@ -0,0 +1,164 @@
+import datetime
+from rest_framework import serializers
+from django.db import transaction
+from django.utils import timezone
+
+from training.models import OnPlatformTraining, Module, Quiz, QuizChoice, ContentBlock
+from user.models import Training, TrainingType
+from notification.utility import notify_users_of_training_expiry
+
+
+NUMBER_OF_DAYS_SET_TO_EXPIRE = 30
+
+
+class QuizChoiceSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = QuizChoice
+        fields = "__all__"
+        read_only_fields = ['id', 'quiz']
+
+
+class QuizSerializer(serializers.ModelSerializer):
+    choices = QuizChoiceSerializer(many=True)
+
+    class Meta:
+        model = Quiz
+        fields = "__all__"
+        read_only_fields = ['id', 'module']
+
+
+class ContentBlockSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = ContentBlock
+        fields = "__all__"
+        read_only_fields = ['id', 'module']
+
+
+class ModuleSerializer(serializers.ModelSerializer):
+    quizzes = QuizSerializer(many=True)
+    contents = ContentBlockSerializer(many=True)
+
+    class Meta:
+        model = Module
+        fields = "__all__"
+        read_only_fields = ['id', 'training']
+
+
+class OnPlatformTrainingSerializer(serializers.ModelSerializer):
+    modules = ModuleSerializer(many=True)
+
+    class Meta:
+        model = OnPlatformTraining
+        fields = "__all__"
+        read_only_fields = ['id', 'training_type']
+
+
+class TrainingTypeSerializer(serializers.ModelSerializer):
+    op_trainings = OnPlatformTrainingSerializer()
+
+    class Meta:
+        model = TrainingType
+        fields = "__all__"
+        read_only_fields = ['id']
+
+    def update_training_for_major_version_change(self, instance):
+        """
+        If it is a major version change, it sets all former user trainings
+        to a reduced date, and informs them all.
+        """
+
+        trainings = Training.objects.filter(
+            training_type=instance,
+            process_datetime__gte=timezone.now() - instance.valid_duration)
+        _ = trainings.update(
+            process_datetime=(
+                timezone.now() - (instance.valid_duration - timezone.timedelta(
+                    days=NUMBER_OF_DAYS_SET_TO_EXPIRE))))
+
+        for training in trainings:
+            notify_users_of_training_expiry(
+                training.user, instance.name, NUMBER_OF_DAYS_SET_TO_EXPIRE)
+
+    def update(self, instance, validated_data):
+
+        with transaction.atomic():
+            op_training = validated_data.pop('op_trainings')
+            modules = op_training.pop('modules')
+
+            op_training['training_type'] = instance
+
+            op_training_instance = OnPlatformTraining.objects.create(**op_training)
+
+            for module in modules:
+                quizzes = module.pop('quizzes')
+                contents = module.pop('contents')
+
+                module['training'] = op_training_instance
+                module_instance = Module.objects.create(**module)
+
+                choice_bulk = []
+                for quiz in quizzes:
+                    choices = quiz.pop('choices')
+
+                    quiz['module'] = module_instance
+                    q = Quiz(**quiz)
+                    q.save()
+
+                    for choice in choices:
+                        choice['quiz'] = q
+                        choice_bulk.append(QuizChoice(**choice))
+
+                QuizChoice.objects.bulk_create(choice_bulk)
+
+                content_bulk = []
+                for content in contents:
+                    content['module'] = module_instance
+                    content_bulk.append(ContentBlock(**content))
+                ContentBlock.objects.bulk_create(content_bulk)
+
+            if op_training.get("version"):
+                if str(op_training.get("version")).endswith("0"):
+                    self.update_training_for_major_version_change(instance)
+
+        return op_training_instance
+
+    def create(self, validated_data):
+
+        with transaction.atomic():
+            op_training = validated_data.pop('op_trainings')
+            modules = op_training.pop('modules')
+
+            op_training['training_type'] = instance = TrainingType.objects.create(**validated_data)
+
+            op_training_instance = OnPlatformTraining.objects.create(**op_training)
+
+            for module in modules:
+                quizzes = module.pop('quizzes')
+                contents = module.pop('contents')
+
+                module['training'] = op_training_instance
+                module_instance = Module.objects.create(**module)
+
+                choice_bulk = []
+                for quiz in quizzes:
+                    choices = quiz.pop('choices')
+
+                    quiz['module'] = module_instance
+                    q = Quiz(**quiz)
+                    q.save()
+
+                    for choice in choices:
+                        choice['quiz'] = q
+                        choice_bulk.append(QuizChoice(**choice))
+
+                QuizChoice.objects.bulk_create(choice_bulk)
+
+                content_bulk = []
+                for content in contents:
+                    content['module'] = module_instance
+                    content_bulk.append(ContentBlock(**content))
+                ContentBlock.objects.bulk_create(content_bulk)
+
+        return instance
diff --git a/physionet-django/training/templates/training/email/training_notification.html b/physionet-django/training/templates/training/email/training_notification.html
new file mode 100644
index 0000000000..c01f26a47a
--- /dev/null
+++ b/physionet-django/training/templates/training/email/training_notification.html
@@ -0,0 +1,9 @@
+{% load i18n %}{% autoescape off %}{% filter wordwrap:70 %}
+Dear {{ name }},
+
+Your training {{ training }} on {{ domain }} will be expiring in {{ expiry }} days. To retain the access it provides, kindly login to your account to retake it.
+
+
+Regards
+The {{ SITE_NAME }} Team
+{% endfilter %}{% endautoescape %}