diff --git a/modules/opencase_cases/src/Form/OCCaseRevisionDeleteForm.php b/modules/opencase_cases/src/Form/OCCaseRevisionDeleteForm.php
index b4a6039..72f90b4 100644
--- a/modules/opencase_cases/src/Form/OCCaseRevisionDeleteForm.php
+++ b/modules/opencase_cases/src/Form/OCCaseRevisionDeleteForm.php
@@ -107,7 +107,7 @@ class OCCaseRevisionDeleteForm extends ConfirmFormBase {
     $this->OCCaseStorage->deleteRevision($this->revision->getRevisionId());
 
     $this->logger('content')->notice('Case: deleted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Revision from %revision-date of Case %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
+    \Drupal::messenger()->addMessage(t('Revision from %revision-date of Case %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
     $form_state->setRedirect(
       'entity.oc_case.canonical',
        ['oc_case' => $this->revision->id()]
diff --git a/modules/opencase_cases/src/Form/OCCaseRevisionRevertForm.php b/modules/opencase_cases/src/Form/OCCaseRevisionRevertForm.php
index 80d158f..f36b44f 100644
--- a/modules/opencase_cases/src/Form/OCCaseRevisionRevertForm.php
+++ b/modules/opencase_cases/src/Form/OCCaseRevisionRevertForm.php
@@ -120,7 +120,7 @@ class OCCaseRevisionRevertForm extends ConfirmFormBase {
     $this->revision->save();
 
     $this->logger('content')->notice('Case: reverted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Case %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
+    \Drupal::messenger()->addMessage(t('Case %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
     $form_state->setRedirect(
       'entity.oc_case.version_history',
       ['oc_case' => $this->revision->id()]
diff --git a/modules/opencase_cases/src/Form/OCCaseTypeDeleteForm.php b/modules/opencase_cases/src/Form/OCCaseTypeDeleteForm.php
index f229674..7b407cf 100644
--- a/modules/opencase_cases/src/Form/OCCaseTypeDeleteForm.php
+++ b/modules/opencase_cases/src/Form/OCCaseTypeDeleteForm.php
@@ -38,7 +38,7 @@ class OCCaseTypeDeleteForm extends EntityConfirmFormBase {
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $this->entity->delete();
 
-    drupal_set_message(
+    \Drupal::messenger()->addMessage(
       $this->t('content @type: deleted @label.',
         [
           '@type' => $this->entity->bundle(),
diff --git a/modules/opencase_cases/src/Form/OCCaseTypeForm.php b/modules/opencase_cases/src/Form/OCCaseTypeForm.php
index 2c42f1b..e0d7cdf 100644
--- a/modules/opencase_cases/src/Form/OCCaseTypeForm.php
+++ b/modules/opencase_cases/src/Form/OCCaseTypeForm.php
@@ -49,13 +49,13 @@ class OCCaseTypeForm extends EntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created the %label Case type.', [
+        \Drupal::messenger()->addMessage($this->t('Created the %label Case type.', [
           '%label' => $oc_case_type->label(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Saved the %label Case type.', [
+        \Drupal::messenger()->addMessage($this->t('Saved the %label Case type.', [
           '%label' => $oc_case_type->label(),
         ]));
     }
diff --git a/modules/opencase_entities/src/Form/OCActivityForm.php b/modules/opencase_entities/src/Form/OCActivityForm.php
index b6fa492..54cdd28 100644
--- a/modules/opencase_entities/src/Form/OCActivityForm.php
+++ b/modules/opencase_entities/src/Form/OCActivityForm.php
@@ -55,19 +55,19 @@ class OCActivityForm extends ContentEntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created the %bundle.', [
+         \Drupal::messenger()->addMessage($this->t('Created the %bundle.', [
           '%bundle' => $entity->bundle(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Saved the %bundle.', [
+         \Drupal::messenger()->addMessage($this->t('Saved the %bundle.', [
           '%bundle' => $entity->bundle(),
         ]));
     }
     // If you have unpublished the entity and you can't see unpublished entities, redirect to a more informative message than just "Access Denied".
     if (!$form_state->getValue('status')['value'] && !\Drupal::currentUser()->hasPermission('view unpublished activity entities')) {
-      drupal_set_message($this->t('The %bundle is now unpublished & hidden from you.', [
+       \Drupal::messenger()->addMessage($this->t('The %bundle is now unpublished & hidden from you.', [
         '%bundle' => $entity->bundle(),
       ]));
       $form_state->setRedirect('<front>');
diff --git a/modules/opencase_entities/src/Form/OCActivityRevisionDeleteForm.php b/modules/opencase_entities/src/Form/OCActivityRevisionDeleteForm.php
index adc276f..c129d3f 100644
--- a/modules/opencase_entities/src/Form/OCActivityRevisionDeleteForm.php
+++ b/modules/opencase_entities/src/Form/OCActivityRevisionDeleteForm.php
@@ -107,7 +107,7 @@ class OCActivityRevisionDeleteForm extends ConfirmFormBase {
     $this->OCActivityStorage->deleteRevision($this->revision->getRevisionId());
 
     $this->logger('content')->notice('Activity: deleted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Revision from %revision-date of Activity %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
+    \Drupal::messenger()->addMessage(t('Revision from %revision-date of Activity %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
     $form_state->setRedirect(
       'entity.oc_activity.canonical',
        ['oc_activity' => $this->revision->id()]
diff --git a/modules/opencase_entities/src/Form/OCActivityRevisionRevertForm.php b/modules/opencase_entities/src/Form/OCActivityRevisionRevertForm.php
index 5fc3c8b..4421559 100644
--- a/modules/opencase_entities/src/Form/OCActivityRevisionRevertForm.php
+++ b/modules/opencase_entities/src/Form/OCActivityRevisionRevertForm.php
@@ -120,7 +120,7 @@ class OCActivityRevisionRevertForm extends ConfirmFormBase {
     $this->revision->save();
 
     $this->logger('content')->notice('Activity: reverted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Activity %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
+    \Drupal::messenger()->addMessage(t('Activity %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
     $form_state->setRedirect(
       'entity.oc_activity.version_history',
       ['oc_activity' => $this->revision->id()]
diff --git a/modules/opencase_entities/src/Form/OCActivityTypeDeleteForm.php b/modules/opencase_entities/src/Form/OCActivityTypeDeleteForm.php
index fd6bf1f..08479d6 100644
--- a/modules/opencase_entities/src/Form/OCActivityTypeDeleteForm.php
+++ b/modules/opencase_entities/src/Form/OCActivityTypeDeleteForm.php
@@ -38,7 +38,7 @@ class OCActivityTypeDeleteForm extends EntityConfirmFormBase {
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $this->entity->delete();
 
-    drupal_set_message(
+    \Drupal::messenger()->addMessage(
       $this->t('content @type: deleted @label.',
         [
           '@type' => $this->entity->bundle(),
diff --git a/modules/opencase_entities/src/Form/OCActivityTypeForm.php b/modules/opencase_entities/src/Form/OCActivityTypeForm.php
index 845106b..21d2c37 100644
--- a/modules/opencase_entities/src/Form/OCActivityTypeForm.php
+++ b/modules/opencase_entities/src/Form/OCActivityTypeForm.php
@@ -49,13 +49,13 @@ class OCActivityTypeForm extends EntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created the %label Activity type.', [
+        \Drupal::messenger()->addMessage($this->t('Created the %label Activity type.', [
           '%label' => $oc_activity_type->label(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Saved the %label Activity type.', [
+        \Drupal::messenger()->addMessage($this->t('Saved the %label Activity type.', [
           '%label' => $oc_activity_type->label(),
         ]));
     }
diff --git a/modules/opencase_entities/src/Form/OCActorForm.php b/modules/opencase_entities/src/Form/OCActorForm.php
index fe23b62..569fe95 100644
--- a/modules/opencase_entities/src/Form/OCActorForm.php
+++ b/modules/opencase_entities/src/Form/OCActorForm.php
@@ -48,19 +48,19 @@ class OCActorForm extends ContentEntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created %label.', [
+        \Drupal::messenger()->addMessage($this->t('Created %label.', [
           '%label' => $entity->label(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Saved %label.', [
+        \Drupal::messenger()->addMessage($this->t('Saved %label.', [
           '%label' => $entity->label(),
         ]));
     }
     // If you have unpublished the entity and you can't see unpublished entities, redirect to a more informative message than just "Access Denied".
     if (!$form_state->getValue('status')['value'] && !\Drupal::currentUser()->hasPermission('view unpublished actor entities')) {
-      drupal_set_message($this->t('The record for "%label" is now unpublished & hidden from you.', [
+      \Drupal::messenger()->addMessage($this->t('The record for "%label" is now unpublished & hidden from you.', [
         '%label' => $entity->label(),
       ]));
       $form_state->setRedirect('<front>');
diff --git a/modules/opencase_entities/src/Form/OCActorRevisionDeleteForm.php b/modules/opencase_entities/src/Form/OCActorRevisionDeleteForm.php
index a4c686b..9650952 100644
--- a/modules/opencase_entities/src/Form/OCActorRevisionDeleteForm.php
+++ b/modules/opencase_entities/src/Form/OCActorRevisionDeleteForm.php
@@ -107,7 +107,7 @@ class OCActorRevisionDeleteForm extends ConfirmFormBase {
     $this->OCActorStorage->deleteRevision($this->revision->getRevisionId());
 
     $this->logger('content')->notice('Actor: deleted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Revision from %revision-date of Actor %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
+    \Drupal::messenger()->addMessage(t('Revision from %revision-date of Actor %title has been deleted.', ['%revision-date' => format_date($this->revision->getRevisionCreationTime()), '%title' => $this->revision->label()]));
     $form_state->setRedirect(
       'entity.oc_actor.canonical',
        ['oc_actor' => $this->revision->id()]
diff --git a/modules/opencase_entities/src/Form/OCActorRevisionRevertForm.php b/modules/opencase_entities/src/Form/OCActorRevisionRevertForm.php
index 0842dcd..e1de412 100644
--- a/modules/opencase_entities/src/Form/OCActorRevisionRevertForm.php
+++ b/modules/opencase_entities/src/Form/OCActorRevisionRevertForm.php
@@ -120,7 +120,7 @@ class OCActorRevisionRevertForm extends ConfirmFormBase {
     $this->revision->save();
 
     $this->logger('content')->notice('Actor: reverted %title revision %revision.', ['%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
-    drupal_set_message(t('Actor %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
+    \Drupal::messenger()->addMessage(t('Actor %title has been reverted to the revision from %revision-date.', ['%title' => $this->revision->label(), '%revision-date' => $this->dateFormatter->format($original_revision_timestamp)]));
     $form_state->setRedirect(
       'entity.oc_actor.version_history',
       ['oc_actor' => $this->revision->id()]
diff --git a/modules/opencase_entities/src/Form/OCActorTypeDeleteForm.php b/modules/opencase_entities/src/Form/OCActorTypeDeleteForm.php
index 2fb46f9..74bdf36 100644
--- a/modules/opencase_entities/src/Form/OCActorTypeDeleteForm.php
+++ b/modules/opencase_entities/src/Form/OCActorTypeDeleteForm.php
@@ -38,7 +38,7 @@ class OCActorTypeDeleteForm extends EntityConfirmFormBase {
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $this->entity->delete();
 
-    drupal_set_message(
+    \Drupal::messenger()->addMessage(
       $this->t('content @type: deleted @label.',
         [
           '@type' => $this->entity->bundle(),
diff --git a/modules/opencase_entities/src/Form/OCActorTypeForm.php b/modules/opencase_entities/src/Form/OCActorTypeForm.php
index 92cff32..dbf1f73 100644
--- a/modules/opencase_entities/src/Form/OCActorTypeForm.php
+++ b/modules/opencase_entities/src/Form/OCActorTypeForm.php
@@ -49,13 +49,13 @@ class OCActorTypeForm extends EntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created the %label Person type.', [
+        \Drupal::messenger()->addMessage($this->t('Created the %label Person type.', [
           '%label' => $oc_actor_type->label(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Saved the %label Person type.', [
+        \Drupal::messenger()->addMessage($this->t('Saved the %label Person type.', [
           '%label' => $oc_actor_type->label(),
         ]));
     }
diff --git a/modules/opencase_entities/src/Form/OCEventForm.php b/modules/opencase_entities/src/Form/OCEventForm.php
index 54affd1..c204446 100644
--- a/modules/opencase_entities/src/Form/OCEventForm.php
+++ b/modules/opencase_entities/src/Form/OCEventForm.php
@@ -62,7 +62,7 @@ class OCEventForm extends ContentEntityForm {
     }
     // If you have unpublished the entity and you can't see unpublished entities, redirect to a more informative message than just "Access Denied".
     if (!$form_state->getValue('status')['value'] && !\Drupal::currentUser()->hasPermission('view unpublished event entities')) {
-      drupal_set_message($this->t('The record for "%label" is now unpublished & hidden from you.', [
+      \Drupal::messenger()->addMessage($this->t('The record for "%label" is now unpublished & hidden from you.', [
         '%label' => $entity->label(),
       ]));
       $form_state->setRedirect('<front>');
diff --git a/modules/opencase_entities/src/Form/OCOrganisationForm.php b/modules/opencase_entities/src/Form/OCOrganisationForm.php
index bf05881..652af4b 100644
--- a/modules/opencase_entities/src/Form/OCOrganisationForm.php
+++ b/modules/opencase_entities/src/Form/OCOrganisationForm.php
@@ -83,7 +83,7 @@ class OCOrganisationForm extends ContentEntityForm {
     }
     // If you have unpublished the entity and you can't see unpublished entities, redirect to a more informative message than just "Access Denied".
     if (!$form_state->getValue('status')['value'] && !\Drupal::currentUser()->hasPermission('view unpublished organisation entities')) {
-      drupal_set_message($this->t('The record for "%label" is now unpublished & hidden from you.', [
+      \Drupal::messenger()->addMessage($this->t('The record for "%label" is now unpublished & hidden from you.', [
         '%label' => $entity->label(),
       ]));
       $form_state->setRedirect('<front>');