diff --git a/composer.json b/composer.json
index a969d54..31845d4 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
     ],
     "require": {
         "ext-json": "*",
-        "phpseclib/phpseclib": "~3.0",
+        "phpseclib/phpseclib": "~2.0",
         "google/cloud-tasks": "^1.10",
         "thecodingmachine/safe": "^1.0|^2.0"
     },