diff --git a/src/utils.py b/src/utils.py
index 879b98d7..2d9a365b 100755
--- a/src/utils.py
+++ b/src/utils.py
@@ -150,7 +150,8 @@ def pytransform_bootstrap(capsule=None, force=False):
     logging.debug('The version of core library is %s', ver)
     if ver[0] < 32:
         raise RuntimeError('PyArmor does not work with this core library '
-                           '(r%d), which reversion < 32' % ver[0])
+                           '(r%d), which reversion < r32, please run '
+                           '"pyarmor download --update" to fix it' % ver[0])
 
     if capsule is not None and not os.path.exists(capsule):
         logging.info('Generating public capsule ...')