diff --git a/db/migrate/20201028095957_issue_3215_rename_existing_office365.rb b/db/migrate/20201028095957_issue_3215_rename_existing_office365.rb
new file mode 100644
index 000000000..77d667c1e
--- /dev/null
+++ b/db/migrate/20201028095957_issue_3215_rename_existing_office365.rb
@@ -0,0 +1,14 @@
+class Issue3215RenameExistingOffice365 < ActiveRecord::Migration[5.2]
+  def change
+
+    # return if it's a new setup
+    return if !Setting.exists?(name: 'system_init_done')
+
+    # migrate existing Channels and ExternalCredential to new name
+
+    # rubocop:disable Rails/SkipsModelValidations
+    Channel.where(area: 'Office365::Account').update_all(name: 'Microsoft365::Account')
+    ExternalCredential.where(name: 'office365').update_all(name: 'microsoft365')
+    # rubocop:enable Rails/SkipsModelValidations
+  end
+end