diff --git a/delivery_correos_express/__manifest__.py b/delivery_correos_express/__manifest__.py
index 604e4d9d90..7731bc2c50 100644
--- a/delivery_correos_express/__manifest__.py
+++ b/delivery_correos_express/__manifest__.py
@@ -3,7 +3,7 @@
 {
     "name": "Delivery Correos Express",
     "summary": "Delivery Carrier implementation for Correos Express using their API",
-    "version": "16.0.1.0.0",
+    "version": "17.0.1.0.0",
     "category": "Stock",
     "website": "https://github.com/OCA/delivery-carrier",
     "author": "Studio73, Odoo Community Association (OCA)",
diff --git a/delivery_correos_express/models/correos_express_request.py b/delivery_correos_express/models/correos_express_request.py
index fa627b11c1..fdbd19415c 100644
--- a/delivery_correos_express/models/correos_express_request.py
+++ b/delivery_correos_express/models/correos_express_request.py
@@ -96,15 +96,15 @@ def _check_for_error(self, result):
         return_code = 999
         message = "Webservice ERROR."
         # shipment
-        if type(result.get("codigoRetorno", "false")) != str:
+        if type(result.get("codigoRetorno", "false")) != isinstance(str):
             return_code = result.get("codigoRetorno")
             message = result.get("mensajeRetorno") or ""
         # label
-        if type(result.get("codErr", "false")) != str:
+        if type(result.get("codErr", "false")) != isinstance(str):
             return_code = result.get("codErr")
             message = result.get("desErr") or ""
         # tracking
-        if type(result.get("error", "false")) != str:
+        if type(result.get("error", "false")) != isinstance(str):
             return_code = result.get("error")
             message = result.get("mensajeError") or ""
         return return_code, message
diff --git a/delivery_correos_express/views/delivery_carrier_view.xml b/delivery_correos_express/views/delivery_carrier_view.xml
index fbf2025ff3..ef592f149a 100644
--- a/delivery_correos_express/views/delivery_carrier_view.xml
+++ b/delivery_correos_express/views/delivery_carrier_view.xml
@@ -7,66 +7,38 @@
             <xpath expr="//notebook/page[1]" position='before'>
                 <page
                     string="Correos Express Configuration"
-                    attrs="{'invisible': [('delivery_type', '!=', 'correos_express')]}"
+                    invisible="delivery_type != 'correos_express'"
                 >
                     <group>
                         <group>
                             <field
                                 name="correos_express_username"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_password"
                                 password="True"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_customer_code"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_sender_code"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_label_type"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_product"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                             <field
                                 name="correos_express_transport"
-                                attrs="{
-                                    'required': [
-                                        ('delivery_type', '=', 'correos_express')
-                                    ]
-                                }"
+                                required="delivery_type == 'correos_express'"
                             />
                         </group>
                     </group>
diff --git a/delivery_correos_express/views/stock_picking_views.xml b/delivery_correos_express/views/stock_picking_views.xml
index e66b2c459f..b39a6c5d25 100644
--- a/delivery_correos_express/views/stock_picking_views.xml
+++ b/delivery_correos_express/views/stock_picking_views.xml
@@ -9,13 +9,7 @@
                     name="correos_express_get_label"
                     string="Print Correos Express Label"
                     type="object"
-                    attrs="{'invisible':[
-                        '|',
-                        '|',
-                        ('carrier_tracking_ref', '=', False),
-                        ('delivery_type', '!=', 'correos_express'),
-                        ('state', '!=', 'done')
-                    ]}"
+                    invisible="(carrier_tracking_ref != True) or (delivery_type != 'correos_express') or (state != 'done')"
                 />
             </xpath>
         </field>