diff --git a/lam/docs/devel/upgrade.htm b/lam/docs/devel/upgrade.htm
index f867206a..8e40fefe 100644
--- a/lam/docs/devel/upgrade.htm
+++ b/lam/docs/devel/upgrade.htm
@@ -19,6 +19,7 @@
 
 
 
+
 
 
 
@@ -48,8 +49,15 @@ This is a list of API changes for all LAM releases.
 <br>
 
 <h2>5.5 -&gt; 5.6</h2>
-Functions in lib/types.inc got namespace LAM/TYPES (e.g. getTypeAlias()).<br>
-New API to access configured account types: LAM\TYPES\TypeManager.<br>
+<ul>
+  <li>
+Functions in lib/types.inc got namespace LAM/TYPES (e.g. getTypeAlias()).</li>
+  <li>
+New API to access configured account types: LAM\TYPES\TypeManager.</li>
+  <li>class baseType: new function getSuffixFilter()<br>
+  </li>
+</ul>
+
 
 <h2>5.4 -&gt; 5.5</h2>Functions Ldap::encrypt/decrypt in ldap.inc moved to lamEncrypt/lamDecrypt in security.inc.<br>
 <br>
diff --git a/lam/lib/baseType.inc b/lam/lib/baseType.inc
index ef208bf1..cf093870 100644
--- a/lam/lib/baseType.inc
+++ b/lam/lib/baseType.inc
@@ -129,6 +129,15 @@ class baseType {
 		return null;
 	}
 
+	/**
+	 * Returns the LDAP filter to find the possible suffixes for this account type.
+	 *
+	 * @return string LDAP filter
+	 */
+	public function getSuffixFilter() {
+		return "(|(objectClass=organizationalunit)(objectClass=country)(objectClass=organization)(objectClass=krbRealmContainer)(objectClass=container))";
+	}
+
 	/**
 	 * Returns a list of LDAP suffixes for this type.
 	 *
@@ -144,7 +153,7 @@ class baseType {
 			$connection = $_SESSION['ldapHandle'];
 		}
 		$ret = array();
-		$filter = "(|(objectClass=organizationalunit)(objectClass=country)(objectClass=organization)(objectClass=krbRealmContainer)(objectClass=container))";
+		$filter = $this->getSuffixFilter();
 		$sr = @ldap_search($connection, escapeDN($suffix),$filter , array('dn', 'objectClass'), 0, 0, 0, LDAP_DEREF_NEVER);
 		if ($sr) {
 			$units = ldap_get_entries($connection, $sr);