diff --git a/cd.sh b/cd.sh
index 251169f..d8e02dc 100644
--- a/cd.sh
+++ b/cd.sh
@@ -66,6 +66,32 @@ cd_set_environment_variables () {
                 | sed "s|^\([0-9]\+\.[0-9]\+\)\..*|\1|")
         ;;
     esac
+    case "${CD_OS_ID}" in
+        "${CD_OS_ALMA}"|"${CD_OS_ROCKY}")
+            case "${CD_OS_VERSION}" in
+                "8"|"9") ;;
+                *) cd_error_os "CD_OS_VERSION" ;;
+            esac
+        ;;
+        "${CD_OS_ALPINE}")
+            case "${CD_OS_VERSION}" in
+                "3.18"|"3.19") ;;
+                *) cd_error_os "CD_OS_VERSION" ;;
+            esac
+        ;;
+        "${CD_OS_DEBIAN}")
+            case "${CD_OS_VERSION}" in
+                "bookworm"|"bullseye") ;;
+                *) cd_error_os "CD_OS_VERSION" ;;
+            esac
+        ;;
+        "${CD_OS_UBUNTU}")
+            case "${CD_OS_VERSION}" in
+                "noble"|"mantic") ;;
+                *) cd_error_os "CD_OS_VERSION" ;;
+            esac
+        ;;
+    esac
     cd_echo "CD_OS_ID" "CD_OS_VERSION"
     # universal
     CD_DNS_FILE="/etc/resolv.conf"
@@ -141,10 +167,6 @@ Dir::Etc::SourceParts \"\";
         "${CD_OS_ALMA}")
             CD_OS_REPO="${CD_DEFAULT_REPO_ALMA}"
             [ "${CD_REPO_ALMA}" ] && CD_OS_REPO="${CD_REPO_ALMA}"
-            case "${CD_OS_VERSION}" in
-                "8"|"9") ;;
-                *) cd_error_os "CD_OS_VERSION" ;;
-            esac
             CD_PKG_PKG=""
             CD_PYTHON_COMMAND="python3.11"
             CD_PYTHON_PACKAGE="python3.11"
@@ -153,10 +175,6 @@ Dir::Etc::SourceParts \"\";
         "${CD_OS_ALPINE}")
             CD_OS_REPO="${CD_DEFAULT_REPO_ALPINE}"
             [ "${CD_REPO_ALPINE}" ] && CD_OS_REPO="${CD_REPO_ALPINE}"
-            case "${CD_OS_VERSION}" in
-                "3.18"|"3.19") ;;
-                *) cd_error_os "CD_OS_VERSION" ;;
-            esac
             CD_PKG_PKG=""
             CD_PYTHON_COMMAND="python3.11"
             CD_PYTHON_PACKAGE="python3"