diff --git a/src/main/java/com/threerings/getdown/data/Application.java b/src/main/java/com/threerings/getdown/data/Application.java
index 3cd0757..caa83a2 100644
--- a/src/main/java/com/threerings/getdown/data/Application.java
+++ b/src/main/java/com/threerings/getdown/data/Application.java
@@ -542,7 +542,7 @@ public class Application
         }
 
         // check if we're overriding the domain in the appbase
-        _appbase = overrideAppbase(_appbase);
+        _appbase = SysProps.overrideAppbase(_appbase);
 
         // make sure there's a trailing slash
         if (!_appbase.endsWith("/")) {
@@ -567,7 +567,7 @@ public class Application
             if (latest.startsWith(_appbase)) {
                 latest = _appbase + latest.substring(_appbase.length());
             } else {
-                latest = replaceDomain(latest);
+                latest = SysProps.replaceDomain(latest);
             }
             try {
                 _latest = new URL(latest);
@@ -1809,31 +1809,6 @@ public class Application
         return cookie.toString();
     }
 
-    /**
-     * Applies {@code appbase_override} or {@code appbase_domain} if they are set.
-     */
-    protected String overrideAppbase (String appbase) {
-        String appbaseOverride = SysProps.appbaseOverride();
-        if (appbaseOverride != null) {
-            return appbaseOverride;
-        } else {
-            return replaceDomain(appbase);
-        }
-    }
-
-    /**
-     * If appbase_domain property is set, replace the domain on the provided string.
-     */
-    protected String replaceDomain (String appbase)
-    {
-        String appbaseDomain = SysProps.appbaseDomain();
-        if (appbaseDomain != null) {
-            Matcher m = Pattern.compile("(http://[^/]+)(.*)").matcher(appbase);
-            appbase = m.replaceAll(appbaseDomain + "$2");
-        }
-        return appbase;
-    }
-
     /**
      * Encodes a path for use in a URL.
      */
diff --git a/src/main/java/com/threerings/getdown/data/SysProps.java b/src/main/java/com/threerings/getdown/data/SysProps.java
index ceb1fab..5238a53 100644
--- a/src/main/java/com/threerings/getdown/data/SysProps.java
+++ b/src/main/java/com/threerings/getdown/data/SysProps.java
@@ -5,6 +5,9 @@
 
 package com.threerings.getdown.data;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 import com.threerings.getdown.util.VersionUtil;
 import com.threerings.getdown.launcher.Getdown;
 
@@ -136,4 +139,29 @@ public class SysProps
             "Regexp '" + propRegex + "' does not match '" + verstr + "' (from " + propName + ")");
         return vers;
     }
+
+    /**
+     * Applies {@code appbase_override} or {@code appbase_domain} if they are set.
+     */
+    public static String overrideAppbase (String appbase) {
+        String appbaseOverride = appbaseOverride();
+        if (appbaseOverride != null) {
+            return appbaseOverride;
+        } else {
+            return replaceDomain(appbase);
+        }
+    }
+
+    /**
+     * If appbase_domain property is set, replace the domain on the provided string.
+     */
+    public static String replaceDomain (String appbase)
+    {
+        String appbaseDomain = appbaseDomain();
+        if (appbaseDomain != null) {
+            Matcher m = Pattern.compile("(https?://[^/]+)(.*)").matcher(appbase);
+            appbase = m.replaceAll(appbaseDomain + "$2");
+        }
+        return appbase;
+    }
 }
diff --git a/src/test/java/com/threerings/getdown/data/SysPropsTest.java b/src/test/java/com/threerings/getdown/data/SysPropsTest.java
new file mode 100644
index 0000000..12a1510
--- /dev/null
+++ b/src/test/java/com/threerings/getdown/data/SysPropsTest.java
@@ -0,0 +1,42 @@
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.data;
+
+import org.junit.*;
+import static org.junit.Assert.*;
+
+public class SysPropsTest {
+
+    @After public void clearProps () {
+        System.clearProperty("appbase_domain");
+        System.clearProperty("appbase_override");
+    }
+
+    public static String[] APPBASES = {
+        "http://foobar.com/myapp",
+        "https://foobar.com/myapp",
+        "http://foobar.com:8080/myapp",
+        "https://foobar.com:8080/myapp"
+    };
+
+    @Test public void testAppbaseDomain () {
+        System.setProperty("appbase_domain", "https://barbaz.com");
+        for (String appbase : APPBASES) {
+            assertEquals("https://barbaz.com/myapp", SysProps.overrideAppbase(appbase));
+        }
+        System.setProperty("appbase_domain", "http://barbaz.com");
+        for (String appbase : APPBASES) {
+            assertEquals("http://barbaz.com/myapp", SysProps.overrideAppbase(appbase));
+        }
+    }
+
+    @Test public void testAppbaseOverride () {
+        System.setProperty("appbase_override", "https://barbaz.com/newapp");
+        for (String appbase : APPBASES) {
+            assertEquals("https://barbaz.com/newapp", SysProps.overrideAppbase(appbase));
+        }
+    }
+}