diff --git a/CHANGELOG.md b/CHANGELOG.md
index 010b1024..c70c630e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,33 @@
+X.Y.Z Release notes
+=============================================================
+### Breaking changes
+* None.
+
+### Enhancements
+* None.
+
+### Bug fixes
+* [Sync] Avoid hammering the ROS authentication service when large numbers of Realms are opened at once.
+
+### Internal
+* None.
+
+
+2.2.15 Release notes (2018-3-9)
+=============================================================
+### Breaking changes
+* None.
+
+### Enhancements
+* None.
+
+### Bug fixes
+* Fixed a bug that could result in notifications from the global notifier being delayed or not delivered at all when multiple Realms change at once.
+
+### Internal
+* None.
+
+
 2.2.14 Release notes (2018-3-5)
 =============================================================
 ### Breaking changes
diff --git a/dependencies.list b/dependencies.list
index 2e946f06..b5b26536 100644
--- a/dependencies.list
+++ b/dependencies.list
@@ -1,5 +1,5 @@
 PACKAGE_NAME=realm-js
-VERSION=2.2.14
+VERSION=2.2.15
 REALM_CORE_VERSION=5.1.2
 REALM_SYNC_VERSION=2.2.15
 REALM_OBJECT_SERVER_VERSION=2.5.1
diff --git a/docs/tutorials/query-language.md b/docs/tutorials/query-language.md
index a7a093e8..57cb0b9a 100644
--- a/docs/tutorials/query-language.md
+++ b/docs/tutorials/query-language.md
@@ -23,7 +23,7 @@ let merlots = wines.filtered('variety == $0 && vintage <= $1', 'Merlot', maxYear
 ```
 
 
-### Relational operators
+### Conditional operators
 You can use equality comparison on all property types: 
 `==` and `!=` 
 
@@ -35,7 +35,7 @@ Example:
 let oldContacts = realm.objects('Contact').filtered('age > 2');
 ```
 
-Note that for boolean properties, you should test against the expected keyword.
+Note that for boolean properties, you should test against `true` or `false`.
 
 Example:
 ```JS
@@ -43,7 +43,7 @@ let women = realm.objects('Contact').filtered('isMale == false');
 ```
 
 ### String operators
-For string properties, prefix, suffix, and substring queries are supported by using the `BEGINSWITH`, `ENDSWITH`, and `CONTAINS` operators.
+For string properties, prefix, suffix, and substring queries are supported by using the `BEGINSWITH`, `ENDSWITH`, `CONTAINS` and `LIKE` operators.
 
 For any string operation you can append `[c]` to the operator to make it case insensitive.
 
@@ -53,6 +53,45 @@ let peopleWhoseNameContainsA = realm.objects('Contact').filtered('name CONTAINS[
 let Johns = realm.objects('Contact').filtered('name ==[c] "john"');
 ```
 
+You can do simple wildcard matching with `LIKE` which supports using `?` to match a single character and `*` to match zero or multiple characters.
+
+Example:
+```JS
+// Matches "John" and "Johnny"
+let Johns = realm.objects('Contact').filtered('name LIKE "John*"');
+```
+
 ### Composition
 Use parentheses and the `&&`/`AND` and `||`/`OR` operators to compose queries. You can negate a predicate with `!`/`NOT`.
 
+### Queries on collections
+
+When objects contain lists you can query into them using the collection operators `ANY`, `ALL` and `NONE`.
+
+Example:
+```JS
+// Find contacts with one or more teenage friends
+let teens = realm.objects('Contact').filtered('ANY friends.age < 14');
+
+// Find contacts where all friends are older than 21
+let adults = realm.objects('Contact').filtered('ALL friends.age > 21');
+```
+
+You can query on aggregates over properties in the lists using the aggregate operators `.@count`, `.@avg`, `.@min`, `.@max` and `.@sum`.
+
+Example:
+```JS
+// Find contacts without friends
+let lonely = realm.objects('Contact').filtered('friends.@count == 0');
+
+// Find contacts where the average age of their friends is above 40
+let adults = realm.objects('Contact').filtered('friends.@avg.age > 40');
+```
+
+Subqueries using the `SUBQUERY` operator allows you to filter the lists across multiple parameters while querying them.
+
+Example:
+```JS
+// Find contacts with friends above 21 in SF
+let teens = realm.objects('Contact').filtered('SUBQUERY(friends, $friend, $friend.age > 21 AND $friend.city = "SF").@count > 0');
+```
diff --git a/lib/index.js b/lib/index.js
index 0458588e..b8350fe1 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -122,7 +122,9 @@ require('./extensions')(realmConstructor);
 if (realmConstructor.Sync) {
     if (getContext() === 'nodejs') {
       nodeRequire('./notifier')(realmConstructor);
-      Object.defineProperty(realmConstructor, 'Worker', {value: nodeRequire('./worker')});
+      if (!realmConstructor.Worker) {
+          Object.defineProperty(realmConstructor, 'Worker', {value: nodeRequire('./worker')});
+      }
     }
 }
 
diff --git a/lib/user-methods.js b/lib/user-methods.js
index 9634ef37..2367837d 100644
--- a/lib/user-methods.js
+++ b/lib/user-methods.js
@@ -36,8 +36,43 @@ function checkTypes(args, types) {
     }
 }
 
-/* global fetch */
-const performFetch = typeof fetch === 'undefined' ? node_require('node-fetch') : fetch;
+// Perform a HTTP request, enqueuing it if too many requests are already in
+// progress to avoid hammering the server.
+const performFetch = (function() {
+    const doFetch = typeof fetch === 'undefined' ? node_require('node-fetch') : fetch;
+    const queue = [];
+    let count = 0;
+    const maxCount = 5;
+    const next = () => {
+        if (count >= maxCount) {
+            return;
+        }
+        const req = queue.shift();
+        if (!req) {
+            return;
+        }
+        const [url, options, resolve, reject] = req;
+        ++count;
+        // node doesn't support Promise.prototype.finally until 10
+        doFetch(url, options)
+            .then(response => {
+                --count;
+                next();
+                resolve(response);
+            })
+            .catch(error => {
+                --count;
+                next();
+                reject(error);
+            });
+    };
+    return (url, options) => {
+        return new Promise((resolve, reject) => {
+            queue.push([url, options, resolve, reject]);
+            next();
+        });
+    };
+})();
 
 const url_parse = require('url-parse');
 
diff --git a/package.json b/package.json
index 22312c5f..41687bcf 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "realm",
   "description": "Realm is a mobile database: an alternative to SQLite and key-value stores",
-  "version": "2.2.14",
+  "version": "2.2.15",
   "license": "Apache-2.0",
   "homepage": "https://realm.io",
   "keywords": [
diff --git a/src/RealmJS.xcodeproj/project.pbxproj b/src/RealmJS.xcodeproj/project.pbxproj
index 32b451ac..1f91bf63 100644
--- a/src/RealmJS.xcodeproj/project.pbxproj
+++ b/src/RealmJS.xcodeproj/project.pbxproj
@@ -961,7 +961,7 @@
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				COPY_PHASE_STRIP = NO;
-				CURRENT_PROJECT_VERSION = 2.2.14;
+				CURRENT_PROJECT_VERSION = 2.2.15;
 				CXX = "$(SRCROOT)/../scripts/ccache-clang++.sh";
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
@@ -1025,7 +1025,7 @@
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				COPY_PHASE_STRIP = NO;
-				CURRENT_PROJECT_VERSION = 2.2.14;
+				CURRENT_PROJECT_VERSION = 2.2.15;
 				CXX = "$(SRCROOT)/../scripts/ccache-clang++.sh";
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;