diff --git a/core/pom.xml b/core/pom.xml
index ee6dbd14ebaddebfabf001583a151dd39f4c4828..de69c2dbda6f66e1a30428a58fff3354ca2e8f32 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -87,6 +87,18 @@ THE SOFTWARE.
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <groupId>org.kohsuke</groupId>
+        <artifactId>access-modifier-checker</artifactId>
+        <version>1.0</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <artifactId>maven-antlr-plugin</artifactId>
         <configuration>
@@ -748,6 +760,12 @@ THE SOFTWARE.
       <version>2.2.3</version>
     </dependency>
 
+    <dependency>
+      <groupId>org.kohsuke</groupId>
+      <artifactId>access-modifier-annotation</artifactId>
+      <version>1.0</version>
+    </dependency>
+
     <!-- offline profiler API to put in the classpath if we need it -->
     <!--dependency>
       <groupId>com.yourkit.api</groupId>
diff --git a/core/src/main/java/hudson/RestrictedSince.java b/core/src/main/java/hudson/RestrictedSince.java
new file mode 100644
index 0000000000000000000000000000000000000000..507c1788c37d01205053c2d26333b012be12ecd1
--- /dev/null
+++ b/core/src/main/java/hudson/RestrictedSince.java
@@ -0,0 +1,43 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2010, Kohsuke Kawaguchi
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package hudson;
+
+import org.kohsuke.accmod.Restricted;
+
+import java.lang.annotation.Documented;
+
+/**
+ * Accompanies {@link Restricted} annotation to indicate when the access restriction was placed.
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.355
+ */
+@Documented
+public @interface RestrictedSince {
+    /**
+     * Hudson version number that this restriction has started.
+     */
+    String value();
+}
diff --git a/core/src/main/java/hudson/model/Hudson.java b/core/src/main/java/hudson/model/Hudson.java
index b97b3dde96e7fece2d79ddae61bba390eb8faaab..715348192cb53b627d9de8bb3be08298c5c1ff80 100644
--- a/core/src/main/java/hudson/model/Hudson.java
+++ b/core/src/main/java/hudson/model/Hudson.java
@@ -145,6 +145,8 @@ import org.jvnet.hudson.reactor.Milestone;
 import org.jvnet.hudson.reactor.Reactor;
 import org.jvnet.hudson.reactor.ReactorListener;
 import org.jvnet.hudson.reactor.TaskGraphBuilder.Handle;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.DoNotUse;
 import org.kohsuke.stapler.Ancestor;
 import org.kohsuke.stapler.HttpRedirect;
 import org.kohsuke.stapler.HttpResponse;
diff --git a/core/src/main/java/hudson/tasks/Mailer.java b/core/src/main/java/hudson/tasks/Mailer.java
index 44baa38f7e7aae81ee1163b249c160d85f44a544..c41ab913a62a0c22c01d95767a7f26a25f8d2b2d 100644
--- a/core/src/main/java/hudson/tasks/Mailer.java
+++ b/core/src/main/java/hudson/tasks/Mailer.java
@@ -26,6 +26,7 @@ package hudson.tasks;
 import hudson.Launcher;
 import hudson.Functions;
 import hudson.Extension;
+import hudson.RestrictedSince;
 import hudson.Util;
 import hudson.diagnosis.OldDataMonitor;
 import static hudson.Util.fixEmptyAndTrim;
@@ -39,6 +40,9 @@ import hudson.util.FormValidation;
 import hudson.util.Secret;
 import hudson.util.XStream2;
 import org.apache.tools.ant.types.selectors.SelectorUtils;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.DoNotUse;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.kohsuke.stapler.QueryParameter;
 import org.kohsuke.stapler.StaplerRequest;
 import org.kohsuke.stapler.export.Exported;
@@ -136,6 +140,8 @@ public class Mailer extends Notifier {
      * @deprecated as of 1.286
      *      Use {@link #descriptor()} to obtain the current instance.
      */
+    @Restricted(NoExternalUse.class)
+    @RestrictedSince("1.355")
     public static DescriptorImpl DESCRIPTOR;
 
     public static DescriptorImpl descriptor() {