diff --git a/src/org/lineageos/updater/misc/LegacySupport.java b/src/org/lineageos/updater/misc/LegacySupport.java
index 962aa43a..557a56b3 100644
--- a/src/org/lineageos/updater/misc/LegacySupport.java
+++ b/src/org/lineageos/updater/misc/LegacySupport.java
@@ -31,6 +31,7 @@ import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.UUID;
 
@@ -153,6 +154,6 @@ public final class LegacySupport {
         if (subStrings.length < 4 || subStrings[3].length() < 7) {
             throw new IllegalFilenameException("The given filename is not valid");
         }
-        return subStrings[3].toLowerCase();
+        return subStrings[3].toLowerCase(Locale.ROOT);
     }
 }
diff --git a/src/org/lineageos/updater/misc/Utils.java b/src/org/lineageos/updater/misc/Utils.java
index 9751da5a..f15be50d 100644
--- a/src/org/lineageos/updater/misc/Utils.java
+++ b/src/org/lineageos/updater/misc/Utils.java
@@ -49,6 +49,7 @@ import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
@@ -149,7 +150,7 @@ public class Utils {
         }
         String incrementalVersion = SystemProperties.get(Constants.PROP_BUILD_VERSION_INCREMENTAL);
         String device = SystemProperties.get(Constants.PROP_DEVICE);
-        String type = SystemProperties.get(Constants.PROP_RELEASE_TYPE).toLowerCase();
+        String type = SystemProperties.get(Constants.PROP_RELEASE_TYPE).toLowerCase(Locale.ROOT);
         return serverUrl + "/v1/" + device + "/" + type + "/" + incrementalVersion;
     }