diff --git a/cohort/externallib.php b/cohort/externallib.php
index 682145960ee..2def3610e95 100644
--- a/cohort/externallib.php
+++ b/cohort/externallib.php
@@ -258,7 +258,7 @@ class core_cohort_external extends external_api {
         return new external_multiple_structure(
             new external_single_structure(
                 array(
-                    'id' => new external_value(PARAM_NUMBER, 'ID of the cohort'),
+                    'id' => new external_value(PARAM_INT, 'ID of the cohort'),
                     'name' => new external_value(PARAM_RAW, 'cohort name'),
                     'idnumber' => new external_value(PARAM_RAW, 'cohort idnumber'),
                     'description' => new external_value(PARAM_RAW, 'cohort description'),
@@ -280,7 +280,7 @@ class core_cohort_external extends external_api {
                 'cohorts' => new external_multiple_structure(
                     new external_single_structure(
                         array(
-                            'id' => new external_value(PARAM_NUMBER, 'ID of the cohort'),
+                            'id' => new external_value(PARAM_INT, 'ID of the cohort'),
                             'categorytype' => new external_single_structure(
                                 array(
                                     'type' => new external_value(PARAM_TEXT, 'the name of the field: id (numeric value
diff --git a/cohort/tests/externallib_test.php b/cohort/tests/externallib_test.php
index d2ad95560bf..c8137fb28c1 100644
--- a/cohort/tests/externallib_test.php
+++ b/cohort/tests/externallib_test.php
@@ -203,6 +203,36 @@ class core_cohort_external_testcase extends externallib_advanced_testcase {
         core_cohort_external::update_cohorts(array($cohort1));
     }
 
+    /**
+     * Verify handling of 'id' param.
+     */
+    public function test_update_cohorts_invalid_id_param() {
+        $this->resetAfterTest(true);
+        $cohort = self::getDataGenerator()->create_cohort();
+
+        $cohort1 = array(
+            'id' => 'THIS IS NOT AN ID',
+            'name' => 'Changed cohort name',
+            'categorytype' => array('type' => 'id', 'value' => '1'),
+            'idnumber' => $cohort->idnumber,
+        );
+
+        try {
+            core_cohort_external::update_cohorts(array($cohort1));
+            $this->fail('Expecting invalid_parameter_exception exception, none occured');
+        } catch (invalid_parameter_exception $e1) {
+            $this->assertContains('Invalid external api parameter: the value is "THIS IS NOT AN ID"', $e1->debuginfo);
+        }
+
+        $cohort1['id'] = 9.999; // Also not a valid id of a cohort.
+        try {
+            core_cohort_external::update_cohorts(array($cohort1));
+            $this->fail('Expecting invalid_parameter_exception exception, none occured');
+        } catch (invalid_parameter_exception $e2) {
+            $this->assertContains('Invalid external api parameter: the value is "9.999"', $e2->debuginfo);
+        }
+    }
+
     /**
      * Test update_cohorts without permission on the dest category.
      */
diff --git a/cohort/upgrade.txt b/cohort/upgrade.txt
new file mode 100644
index 00000000000..d776e6f5cf4
--- /dev/null
+++ b/cohort/upgrade.txt
@@ -0,0 +1,9 @@
+This files describes API changes in /cohort/ information provided here is intended
+especially for developers.
+
+=== 2.6 ===
+* Webservice core_cohort_update_cohorts was incorrectly specifiying float as the parameter type
+  for cohort id. This field is actually int and input is now reported and processed as such.
+* Webservice core_cohort_get_cohorts was incorrectly specifiying float as the return
+  type for cohort id. The actual return type is int and is now reported as such.
+
diff --git a/enrol/externallib.php b/enrol/externallib.php
index f7f08046533..2c4d3ac17a4 100644
--- a/enrol/externallib.php
+++ b/enrol/externallib.php
@@ -197,7 +197,7 @@ class core_enrol_external extends external_api {
                     'users' => new external_multiple_structure(
                         new external_single_structure(
                 array(
-                    'id'    => new external_value(PARAM_NUMBER, 'ID of the user'),
+                    'id'    => new external_value(PARAM_INT, 'ID of the user'),
                     'username'    => new external_value(PARAM_RAW, 'Username', VALUE_OPTIONAL),
                     'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
                     'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
diff --git a/enrol/upgrade.txt b/enrol/upgrade.txt
index 6b606a49ea1..dc6d2c09f76 100644
--- a/enrol/upgrade.txt
+++ b/enrol/upgrade.txt
@@ -6,6 +6,9 @@ information provided here is intended especially for developers.
 * Enrolment plugin which supports self enrolment should implement can_self_enrol()
 * Enrolment plugin should implement get_enrol_info() to expose instance information
   with webservice or external interface.
+* Webservice core_enrol_get_enrolled_users_with_capability was incorrectly specifing
+  float as the return type for user id. int is the actual returned type and is now
+  reported as such.
 
 === 2.5 ===