--- a/sat/memory/disco.py	Fri Mar 01 17:42:28 2019 +0100
+++ b/sat/memory/disco.py	Fri Mar 01 19:28:11 2019 +0100
@@ -356,6 +356,7 @@
 
         """
         s = []
+        # identities
         byte_identities = [
             ByteIdentity(service)
             for service in services
@@ -367,6 +368,7 @@
         for identity in byte_identities:
             s.append(str(identity))
             s.append("<")
+        # features
         byte_features = [
             service.encode("utf-8")
             for service in services
@@ -376,9 +378,26 @@
         for feature in byte_features:
             s.append(feature)
             s.append("<")
-        # TODO: manage XEP-0128 data form here
+
+        # extensions
+        ext = services.extensions.values()
+        ext.sort(key=lambda f: f.formNamespace.encode('utf-8'))
+        for extension in ext:
+            s.append(extension.formNamespace.encode('utf-8'))
+            s.append("<")
+            fields = extension.fieldList
+            fields.sort(key=lambda f: f.var.encode('utf-8'))
+            for field in fields:
+                s.append(field.var.encode('utf-8'))
+                s.append("<")
+                values = [v.encode('utf-8') for v in field.values]
+                values.sort()
+                for value in values:
+                    s.append(value)
+                    s.append("<")
+
         cap_hash = b64encode(sha1("".join(s)).digest())
-        log.debug(_(u"Capability hash generated: [%s]") % cap_hash)
+        log.debug(_(u"Capability hash generated: [{cap_hash}]").format(cap_hash=cap_hash))
         return cap_hash
 
     @defer.inlineCallbacks

--- a/sat/plugins/plugin_xep_0115.py	Fri Mar 01 17:42:28 2019 +0100
+++ b/sat/plugins/plugin_xep_0115.py	Fri Mar 01 19:28:11 2019 +0100
@@ -165,9 +165,10 @@
         if c_hash != "sha-1":  # unknown hash method
             log.warning(
                 _(
-                    u"Unknown hash method for entity capabilities: [%(hash_method)s] (entity: %(jid)s, node: %(node)s)"
+                    u"Unknown hash method for entity capabilities: [{hash_method}] "
+                    u"(entity: {entity_jid}, node: {node})"
                 )
-                % {"hash_method": c_hash, "jid": from_jid, "node": c_node}
+                .format(hash_method = c_hash, entity_jid = from_jid, node = c_node)
             )
 
         def cb(__):
@@ -177,14 +178,16 @@
             if computed_hash != c_ver:
                 log.warning(
                     _(
-                        u"Computed hash differ from given hash:\ngiven: [%(given_hash)s]\ncomputed: [%(computed_hash)s]\n(entity: %(jid)s, node: %(node)s)"
+                        u"Computed hash differ from given hash:\n"
+                        u"given: [{given}]\n"
+                        u"computed: [{computed}]\n"
+                        u"(entity: {entity_jid}, node: {node})"
+                    ).format(
+                        given = c_ver,
+                        computed = computed_hash,
+                        entity_jid = from_jid,
+                        node = c_node,
                     )
-                    % {
-                        "given_hash": c_ver,
-                        "computed_hash": computed_hash,
-                        "jid": from_jid,
-                        "node": c_node,
-                    }
                 )
 
         def eb(failure):