diff --git a/development/mcrl2/mcrl2.info b/development/mcrl2/mcrl2.info
index 6c55df55e2..a5ea44ca71 100644
--- a/development/mcrl2/mcrl2.info
+++ b/development/mcrl2/mcrl2.info
@@ -1,7 +1,7 @@
 PRGNAM="mcrl2"
 VERSION="201409.1"
-HOMEPAGE="http://www.mcrl2.org"
-DOWNLOAD="http://www.mcrl2.org/download/release/mcrl2-201409.1.tar.gz"
+HOMEPAGE="https://www.mcrl2.org"
+DOWNLOAD="https://www.mcrl2.org/download/release/mcrl2-201409.1.tar.gz"
 MD5SUM="32818c4111aa406033e865c30ac7862b"
 DOWNLOAD_x86_64=""
 MD5SUM_x86_64=""
diff --git a/development/mcrl2/slack-desc b/development/mcrl2/slack-desc
index 2f9ed87f4a..fca6abcb59 100644
--- a/development/mcrl2/slack-desc
+++ b/development/mcrl2/slack-desc
@@ -14,6 +14,6 @@ mcrl2: behaviour of distributed systems and protocols and is the successor
 mcrl2: to mCRL. Using its accompanying toolset systems can be analysed and
 mcrl2: verified automatically.
 mcrl2:
-mcrl2: http://www.mcrl2.org/
+mcrl2: https://www.mcrl2.org/
 mcrl2:
 mcrl2: