diff --git a/resources/definitions/ultimaker3.def.json b/resources/definitions/ultimaker3.def.json
index ae36d6a3ae..bd7e96448a 100644
--- a/resources/definitions/ultimaker3.def.json
+++ b/resources/definitions/ultimaker3.def.json
@@ -30,7 +30,7 @@
             "id": 9066,
             "check_urls":
             [
-                "http://software.ultimaker.com/releases/firmware/9066/stable/um-update.swu.version"
+                "https://software.ultimaker.com/releases/firmware/9066/stable/um-update.swu.version"
             ],
             "update_url": "https://ultimaker.com/firmware"
         }
diff --git a/resources/definitions/ultimaker3_extended.def.json b/resources/definitions/ultimaker3_extended.def.json
index b3fe48ca11..c0d099366d 100644
--- a/resources/definitions/ultimaker3_extended.def.json
+++ b/resources/definitions/ultimaker3_extended.def.json
@@ -27,7 +27,7 @@
             "id": 9511,
             "check_urls":
             [
-                "http://software.ultimaker.com/releases/firmware/9066/stable/um-update.swu.version"
+                "https://software.ultimaker.com/releases/firmware/9066/stable/um-update.swu.version"
             ],
             "update_url": "https://ultimaker.com/firmware"
         }
diff --git a/resources/definitions/ultimaker_s5.def.json b/resources/definitions/ultimaker_s5.def.json
index bf60d84890..81b3a704ff 100644
--- a/resources/definitions/ultimaker_s5.def.json
+++ b/resources/definitions/ultimaker_s5.def.json
@@ -33,7 +33,7 @@
         "weight": -2,
         "firmware_update_info": {
             "id": 9051,
-            "check_urls": ["http://software.ultimaker.com/releases/firmware/9051/stable/um-update.swu.version"],
+            "check_urls": ["https://software.ultimaker.com/releases/firmware/9051/stable/um-update.swu.version"],
             "update_url": "https://ultimaker.com/firmware"
         }
     },