diff --git a/History.md b/History.md
index 295b977fec..a71f15b9be 100644
--- a/History.md
+++ b/History.md
@@ -325,6 +325,10 @@
 
 * Fix `Error: Can't render headers after they are sent to the client`.  #4253 #4750
 
+* `Meteor.settings.public` is always available on client and server,
+  and modifications made on the server (for example, during app initialization)
+  affect the value seen by connecting clients. #4704
+
 ### Windows
 
 * Increase the buffer size for `netstat` when looking for running Mongo servers.
diff --git a/packages/meteor/client_environment.js b/packages/meteor/client_environment.js
index 4e894e0e0f..9f8be953b5 100644
--- a/packages/meteor/client_environment.js
+++ b/packages/meteor/client_environment.js
@@ -25,7 +25,7 @@ Meteor = {
 if (typeof __meteor_runtime_config__ === 'object' &&
     __meteor_runtime_config__.PUBLIC_SETTINGS) {
   /**
-   * @summary `Meteor.settings` contains deployment-specific configuration options. You can initialize settings by passing the `--settings` option (which takes the name of a file containing JSON data) to `meteor run` or `meteor deploy`. When running your server directly (e.g. from a bundle), you instead specify settings by putting the JSON directly into the `METEOR_SETTINGS` environment variable. If you don't provide any settings, `Meteor.settings` will be an empty object.  If the settings object contains a key named `public`, then `Meteor.settings.public` will be available on the client as well as the server.  All other properties of `Meteor.settings` are only defined on the server.
+   * @summary `Meteor.settings` contains deployment-specific configuration options. You can initialize settings by passing the `--settings` option (which takes the name of a file containing JSON data) to `meteor run` or `meteor deploy`. When running your server directly (e.g. from a bundle), you instead specify settings by putting the JSON directly into the `METEOR_SETTINGS` environment variable. If the settings object contains a key named `public`, then `Meteor.settings.public` will be available on the client as well as the server.  All other properties of `Meteor.settings` are only defined on the server.  You can rely on `Meteor.settings` and `Meteor.settings.public` being defined objects (not undefined) on both client and server even if there are no settings specified.  Changes to `Meteor.settings.public` at runtime will be picked up by new client connections.
    * @locus Anywhere
    * @type {Object}
    */
diff --git a/packages/meteor/server_environment.js b/packages/meteor/server_environment.js
index a5e186182c..b0c7cbb5bf 100644
--- a/packages/meteor/server_environment.js
+++ b/packages/meteor/server_environment.js
@@ -20,7 +20,11 @@ if (! Meteor.settings.public) {
     Meteor.settings.public = {};
 }
 
-// Push a subset of settings to the client.
+// Push a subset of settings to the client.  Note that the way this
+// code is written, if the app mutates `Meteor.settings.public` on the
+// server, it also mutates
+// `__meteor_runtime_config__.PUBLIC_SETTINGS`, and the modified
+// settings will be sent to the client.
 if (typeof __meteor_runtime_config__ === "object") {
   __meteor_runtime_config__.PUBLIC_SETTINGS = Meteor.settings.public;
 }