diff --git a/.rultor.yml b/.rultor.yml
index 45c9f35..03bd784 100644
--- a/.rultor.yml
+++ b/.rultor.yml
@@ -2,8 +2,8 @@ architect:
 - yegor256
 - dmarkov
 install:
-- sudo gem install pdd
-- sudo gem install xcop
+- sudo gem install pdd -v 0.20.5
+- sudo gem install xcop -v 0.6
 assets:
   secring.gpg: yegor256/home#assets/secring.gpg
   settings.xml: yegor256/home#assets/jcabi/settings.xml