diff --git a/src/Serialization.php b/src/Serialization.php
index 2de4d62b7..8a434e88f 100644
--- a/src/Serialization.php
+++ b/src/Serialization.php
@@ -223,15 +223,18 @@ abstract class Serialization
         if ($settings instanceof Settings) {
             $settings = $settings->getDb();
         }
+        $prefix = null;
         if ($unserialized instanceof DriverArray
             || $unserialized instanceof DbArrayBuilder
-            || (!$exists && $settings instanceof DriverDatabaseAbstract)
+            || (
+                !$exists
+                && $settings instanceof DriverDatabaseAbstract
+                && $prefix = $settings->getEphemeralFilesystemPrefix()
+            )
         ) {
             $tableName = null;
             $array = null;
-            if ($settings instanceof DriverDatabaseAbstract
-                && $prefix = $settings->getEphemeralFilesystemPrefix()
-            ) {
+            if ($prefix !== null) {
                 $tableName = "{$prefix}_MTProto_session";
             } elseif ($unserialized instanceof DriverArray) {
                 $unserialized = (array) $unserialized;
diff --git a/tools/phar.php b/tools/phar.php
index 20071230b..b0cacc29a 100644
--- a/tools/phar.php
+++ b/tools/phar.php
@@ -140,7 +140,7 @@ class Installer
                     'Content-Type: application/json',
                     sprintf(
                         'User-Agent: Composer/%s (%s; %s; %s; %s%s)',
-                        'MProto v7',
+                        'MP v8',
                         \function_exists('php_uname') ? @php_uname('s') : 'Unknown',
                         \function_exists('php_uname') ? @php_uname('r') : 'Unknown',
                         $phpVersion,