diff --git a/src/conf/checkstyle-suppressions.xml b/src/conf/checkstyle-suppressions.xml
index 030b78faa..d39ca01bb 100644
--- a/src/conf/checkstyle-suppressions.xml
+++ b/src/conf/checkstyle-suppressions.xml
@@ -18,7 +18,7 @@
 
 <!DOCTYPE suppressions PUBLIC
      "-//Puppy Crawl//DTD Suppressions 1.0//EN"
-     "http://www.puppycrawl.com/dtds/suppressions_1_0.dtd">
+     "https://checkstyle.org/dtds/suppressions_1_0.dtd">
 
 <suppressions>
   <!-- Suppress switch fallthrough / default case for class Flat3Map -->