diff --git a/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateRoleAccess.php b/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateRoleAccess.php
deleted file mode 100644
index cbfc1186e74..00000000000
--- a/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateRoleAccess.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php
-
-namespace PKP\migration\upgrade\v3_5_0;
-
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Support\Facades\Schema;
-use PKP\migration\Migration;
-
-class I10403_EmailTemplateRoleAccess extends Migration
-{
-    /**
-     * Run the migrations.
-     */
-    public function up(): void
-    {
-
-        Schema::create('email_template_user_group_access', function (Blueprint $table) {
-            $table->bigInteger('email_template_user_group_access_id')->autoIncrement();
-            $table->string('email_key', 255);
-            $table->bigInteger('context_id');
-            $table->bigInteger('user_group_id')->nullable();
-
-            $table->foreign('context_id')->references('journal_id')->on('journals')->onDelete('cascade');
-            $table->foreign('user_group_id')->references('user_group_id')->on('user_groups')->onDelete('cascade');
-        });
-    }
-
-    /**
-     * Reverse the migrations.
-     */
-    public function down(): void
-    {
-        Schema::drop('email_template_user_group_access');
-    }
-}
diff --git a/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateUserGroupAccess.php b/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateUserGroupAccess.php
new file mode 100644
index 00000000000..fb4b75a2e55
--- /dev/null
+++ b/classes/migration/upgrade/v3_5_0/I10403_EmailTemplateUserGroupAccess.php
@@ -0,0 +1,75 @@
+<?php
+
+namespace PKP\migration\upgrade\v3_5_0;
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use PKP\context\Context;
+use PKP\emailTemplate\EmailTemplateAccessGroup;
+use PKP\migration\Migration;
+
+class I10403_EmailTemplateUserGroupAccess extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        $contextDao = \APP\core\Application::getContextDAO();
+        Schema::create('email_template_user_group_access', function (Blueprint $table) use ($contextDao) {
+            $table->bigInteger('email_template_user_group_access_id')->autoIncrement();
+            $table->string('email_key', 255);
+            $table->bigInteger('context_id');
+            $table->bigInteger('user_group_id')->nullable();
+
+            $table->foreign('context_id')->references($contextDao->primaryKeyColumn)->on($contextDao->tableName)->onDelete('cascade');
+            $table->foreign('user_group_id')->references('user_group_id')->on('user_groups')->onDelete('cascade');
+        });
+
+        $contextIds = array_map(fn (Context $context) => $context->getId(), $contextDao->getAll()->toArray());
+
+        if (!empty($contextIds)) {
+            DB::table('email_template_user_group_access')->select('*')->get();
+
+            $defaultTemplateKeys = DB::table('email_templates_default_data')->select()->pluck('email_key')->all();
+            $alternateTemplates = DB::table('email_templates')->select(['context_id', 'email_key'])->get()->toArray();
+
+            $data = [];
+
+            // Record any existing default templates as unrestricted for existing Contexts
+            foreach ($defaultTemplateKeys as $defaultTemplateKey) {
+                foreach ($contextIds as $contextId) {
+                    $data[] = [
+                        'email_key' => $defaultTemplateKey,
+                        'context_id' => $contextId,
+                        'user_group_id' => null
+                    ];
+                }
+            }
+
+            // For any existing alternate template, register it as unrestricted within its assigned context
+            foreach ($alternateTemplates as $template) {
+                foreach ($contextIds as $contextId) {
+                    if ($contextId === $template->context_id) {
+                        $data[] = [
+                            'email_key' => $template->email_key,
+                            'context_id' => $contextId,
+                            'user_group_id' => null
+                        ];
+                    }
+                }
+            }
+
+            EmailTemplateAccessGroup::insert($data);
+        }
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::drop('email_template_user_group_access');
+    }
+}