diff --git a/.rultor.yml b/.rultor.yml
index 3301271..4d6ad71 100644
--- a/.rultor.yml
+++ b/.rultor.yml
@@ -21,7 +21,7 @@
 # SOFTWARE.
 ---
 docker:
-  image: yegor256/rultor-image:1.21.0
+  image: yegor256/rultor-image:1.23.1
 install: |-
   sudo gem install texsc:0.6.0
   sudo gem install texqc:0.6.0