diff --git a/mod/forum/db/upgrade.php b/mod/forum/db/upgrade.php
index ec874dfa7ee..c7248d31979 100644
--- a/mod/forum/db/upgrade.php
+++ b/mod/forum/db/upgrade.php
@@ -242,6 +242,13 @@ function xmldb_forum_upgrade($oldversion) {
 
     // Moodle v2.9.0 release upgrade line.
     // Put any upgrade step following this.
+    if ($oldversion < 2015051102) {
+        // Groupid = 0 is never valid.
+        $DB->set_field('forum_discussions', 'groupid', -1, array('groupid' => 0));
+
+        // Forum savepoint reached.
+        upgrade_mod_savepoint(true, 2015051102, 'forum');
+    }
 
     return true;
 }
diff --git a/mod/forum/tests/behat/separate_group_discussions.feature b/mod/forum/tests/behat/separate_group_discussions.feature
index 2a99b8c4ef9..30e5b506924 100644
--- a/mod/forum/tests/behat/separate_group_discussions.feature
+++ b/mod/forum/tests/behat/separate_group_discussions.feature
@@ -239,3 +239,16 @@ Feature: Posting to all groups in a separate group discussion is restricted to u
     And the "Group" select box should contain "Group A"
     And the "Group" select box should contain "Group B"
     And I should see "Post a copy to all groups"
+
+  Scenario: Students can view all participants discussions in separate groups mode
+    Given I log in as "teacher1"
+    And I follow "Course 1"
+    When I add a new discussion to "Standard forum name" forum with:
+      | Subject | Forum post to all participants |
+      | Message | This is the body |
+      | Group   | All participants |
+    And I log out
+    And I log in as "student1"
+    And I follow "Course 1"
+    And I follow "Standard forum name"
+    Then I should see "Forum post to all participants"
diff --git a/mod/forum/version.php b/mod/forum/version.php
index 2caf094cb05..b6c95cfb4bc 100644
--- a/mod/forum/version.php
+++ b/mod/forum/version.php
@@ -24,6 +24,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2015051101;       // The current module version (Date: YYYYMMDDXX)
+$plugin->version   = 2015051102;       // The current module version (Date: YYYYMMDDXX)
 $plugin->requires  = 2015050500;       // Requires this Moodle version
 $plugin->component = 'mod_forum';      // Full name of the plugin (used for diagnostics)