diff --git a/Layout/default/Preorder/Form.php b/Layout/default/Preorder/Form.php
index 66ef4c02e..54dfa1553 100644
--- a/Layout/default/Preorder/Form.php
+++ b/Layout/default/Preorder/Form.php
@@ -153,7 +153,7 @@
                     <div class="col-lg-10">
                       <select class="form-control" name="adb_wohneinheit_id" id="adb_wohneinheit_id" <?=($preorder && $preorder->adb_wohneinheit_id && is_array($preorder->adb_wohneinheit->rimo_workorders) && count($preorder->adb_wohneinheit->rimo_workorders)) ? "disabled='disabled'" : ""?>>
                       <?php if($preorder->adb_wohneinheit_id): ?>
-                        <option value="<?=$preorder->adb_wohneinheit_id?>" selected="selected"><?=$preorder->adb_hausnummer->strasse->name?> <?=$preorder->adb_hausnummer->hausnummer?> <?=$preorder->adb_wohneinheit?><?=($preorder->adb_wohneinheit->extref) ? " (".$preorder->adb_wohneinheit->extref.")" : ""?></option>
+                        <option value="<?=$preorder->adb_wohneinheit_id?>" selected="selected"><?=$preorder->adb_hausnummer->strasse->name?> <?=$preorder->adb_hausnummer->hausnummer?> <?=$preorder->adb_wohneinheit?><?=($preorder->adb_wohneinheit->extref) ? " (".$preorder->adb_wohneinheit->extref.")" : ""?><?=($preorder->adb_wohneinheit->oaid) ?: ""?><?=(count($preorder->adb_wohneinheit->preorders)) ? " [".count($preorder->adb_wohneinheit->preorders)." Bestellungen]" : ""?></option>
                       <?php endif; ?>
                       </select>
                         <?php if($preorder && $preorder->adb_wohneinheit_id && is_array($preorder->adb_wohneinheit->rimo_workorders) && count($preorder->adb_wohneinheit->rimo_workorders)): ?>
@@ -597,6 +597,8 @@
             opt += " " + unit.extra;
           }
           if(unit.extref) opt += " (" + unit.extref + ")";
+          if(unit.oaid) opt += " - " + unit.oaid;
+          if(unit.preorder_count) opt += " - " + unit.preorder_count + " Bestellung";
           
           /*let extras = new Array();
           if(unit.block) extras.push("Block " + unit.block);
@@ -626,7 +628,9 @@
               .data("stiege", unit.stiege)
               .data("stock", unit.stock)
               .data("tuer", unit.tuer)
-              .data("zusatz", unit.zusatz);
+              .data("zusatz", unit.zusatz)
+              .data("oaid", unit.oaid)
+              .data["preorder_count"];
           
           afterHausnummerChange();
           
diff --git a/application/ADBWohneinheit/ADBWohneinheit.php b/application/ADBWohneinheit/ADBWohneinheit.php
index ea2e3df16..7a1581a8b 100644
--- a/application/ADBWohneinheit/ADBWohneinheit.php
+++ b/application/ADBWohneinheit/ADBWohneinheit.php
@@ -7,6 +7,7 @@ class ADBWohneinheit extends mfBaseModel {
   private $ftu_data;
   private $status;
   private $statusflags; // TODO
+  private $preorders;
   
   protected function init() {
     $this->db = FronkDB::singleton(ADDRESSDB_DBHOST, ADDRESSDB_DBUSER, ADDRESSDB_DBPASS, ADDRESSDB_DBNAME);
@@ -283,6 +284,15 @@ class ADBWohneinheit extends mfBaseModel {
             return $this->rimo_workorders;
         }
 
+        if($name == "preorders") {
+            $preorders = PreorderModel::search(["adb_wohneinheit_id" => $this->id]);
+            if(!count($preorders)) {
+                return [];
+            }
+            $this->preorders = $preorders;
+            return $this->preorders;
+        }
+
       if($name == "ftu_data") {
         $rimo_data = $this->getExternalRimoData();
         
diff --git a/application/AddressDB/AddressDBController.php b/application/AddressDB/AddressDBController.php
index 775afff86..abb0e9048 100644
--- a/application/AddressDB/AddressDBController.php
+++ b/application/AddressDB/AddressDBController.php
@@ -1065,6 +1065,8 @@ class AddressDBController extends mfBaseController {
       $u['extra'] = (string)$unit;
       $u['zusatz'] = $unit->zusatz;
       $u['usage'] = $unit->nutzung;
+      $u['oaid'] = $unit->oaid;
+      $u['preorder_count'] = count($unit->preorders);
       $results[] = $u;
     }
 
diff --git a/application/Preorder/PreorderController.php b/application/Preorder/PreorderController.php
index f60b80b4d..6637745aa 100644
--- a/application/Preorder/PreorderController.php
+++ b/application/Preorder/PreorderController.php
@@ -496,6 +496,14 @@ class PreorderController extends mfBaseController {
             $data['create_by'] = $this->me->id;
             $preorder = PreorderModel::create($data);
         } else {
+            // if new wohneinheit -> remove oaid from Preorder
+            if($r->adb_wohneinheit_id && $preorder->adb_wohneinheit_id != $r->adb_wohneinheit_id) {
+                $preorder->oaid = null;
+            }
+            if(!$r->adb_wohneinheit_id && $preorder->oaid) {
+                $preorder->oaid = null;
+            }
+
             $preorder->update($data);
         }
 
@@ -655,6 +663,9 @@ class PreorderController extends mfBaseController {
                 }
 
             }
+        } else {
+            // if $preorder->adb_wohneinheit_id
+            //if($preorder->_old)
         }
 
         /*