diff --git a/Documentation/dev-contributing.txt b/Documentation/dev-contributing.txt
index bc9f782..8710a2b 100644
--- a/Documentation/dev-contributing.txt
+++ b/Documentation/dev-contributing.txt
@@ -166,7 +166,7 @@
 link:https://github.com/google/google-java-format[`google-java-format`]
 tool (version 1.6), and to format Bazel BUILD, WORKSPACE and .bzl files the
 link:https://github.com/bazelbuild/buildtools/tree/master/buildifier[`buildifier`]
-tool (version 0.15.0).
+tool (version 0.17.2).
 These tools automatically apply format according to the style guides; this
 streamlines code review by reducing the need for time-consuming, tedious,
 and contentious discussions about trivial issues like whitespace.
diff --git a/WORKSPACE b/WORKSPACE
index 37080b7..a5dbbaf 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -30,9 +30,9 @@
     urls = ["https://raw.githubusercontent.com/google/closure-compiler/35d2b3340ff23a69441f10fa3bc820691c2942f2/contrib/externs/polymer-1.0.js"],
 )
 
-load("@bazel_skylib//:lib.bzl", "versions")
+load("@bazel_skylib//lib:versions.bzl", "versions")
 
-versions.check(minimum_bazel_version = "0.17.1")
+versions.check(minimum_bazel_version = "0.19.0")
 
 load("@io_bazel_rules_closure//closure:defs.bzl", "closure_repositories")
 
@@ -759,7 +759,7 @@
     sha1 = "bb562ee73f740bb6b2bf7955f97be6b870d9e9f0",
 )
 
-# When updading Bouncy Castle, also update it in bazlets.
+# When updating Bouncy Castle, also update it in bazlets.
 BC_VERS = "1.60"
 
 maven_jar(
@@ -833,10 +833,18 @@
     sha1 = "f5aa318bda4c6c8d688c9d00b90681dcd82ce636",
 )
 
+# elasticsearch-rest-client explicitly depends on this version
 maven_jar(
-    name = "httpmime",
-    artifact = "org.apache.httpcomponents:httpmime:" + HTTPCOMP_VERS,
-    sha1 = "2f8757f5ac5e38f46c794e5229d1f3c522e9b1df",
+    name = "httpasyncclient",
+    artifact = "org.apache.httpcomponents:httpasyncclient:4.1.2",
+    sha1 = "95aa3e6fb520191a0970a73cf09f62948ee614be",
+)
+
+# elasticsearch-rest-client explicitly depends on this version
+maven_jar(
+    name = "httpcore-nio",
+    artifact = "org.apache.httpcomponents:httpcore-nio:4.4.5",
+    sha1 = "f4be009e7505f6ceddf21e7960c759f413f15056",
 )
 
 # Test-only dependencies below.
@@ -956,9 +964,9 @@
 
 maven_jar(
     name = "derby",
-    artifact = "org.apache.derby:derby:10.11.1.1",
+    artifact = "org.apache.derby:derby:10.12.1.1",
     attach_source = False,
-    sha1 = "df4b50061e8e4c348ce243b921f53ee63ba9bbe1",
+    sha1 = "75070c744a8e52a7d17b8b476468580309d5cd09",
 )
 
 JETTY_VERS = "9.4.12.v20180830"
@@ -1038,8 +1046,8 @@
 
 maven_jar(
     name = "postgresql",
-    artifact = "org.postgresql:postgresql:42.2.4",
-    sha1 = "dff98730c28a4b3a3263f0cf4abb9a3392f815a7",
+    artifact = "org.postgresql:postgresql:42.2.5",
+    sha1 = "951b7eda125f3137538a94e2cbdcf744088ad4c2",
 )
 
 maven_jar(
@@ -1079,10 +1087,12 @@
     sha1 = "76716d529710fc03d1d429b43e3cedd4419f78d4",
 )
 
+# When upgrading elasticsearch-rest-client, also upgrade http-niocore
+# and httpasyncclient as necessary.
 maven_jar(
     name = "elasticsearch-rest-client",
-    artifact = "org.elasticsearch.client:elasticsearch-rest-client:6.4.2",
-    sha1 = "a2baf2d4fdf03f31fbd39351a32bee25fcdfa1cf",
+    artifact = "org.elasticsearch.client:elasticsearch-rest-client:6.4.3",
+    sha1 = "5c24325430971ba2fa4769eb446f026b7680d5e7",
 )
 
 JACKSON_VERSION = "2.9.7"
@@ -1094,18 +1104,6 @@
 )
 
 maven_jar(
-    name = "httpasyncclient",
-    artifact = "org.apache.httpcomponents:httpasyncclient:4.1.2",
-    sha1 = "95aa3e6fb520191a0970a73cf09f62948ee614be",
-)
-
-maven_jar(
-    name = "httpcore-nio",
-    artifact = "org.apache.httpcomponents:httpcore-nio:" + HTTPCOMP_VERS,
-    sha1 = "a8c5e3c3bfea5ce23fb647c335897e415eb442e3",
-)
-
-maven_jar(
     name = "testcontainers",
     artifact = "org.testcontainers:testcontainers:1.8.0",
     sha1 = "bc413912f7044f9f12aa0782853aef0a067ee52a",
diff --git a/java/com/google/gerrit/extensions/api/changes/ChangeApi.java b/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
index 0150e1e..dfa2128 100644
--- a/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
+++ b/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
@@ -49,17 +49,21 @@
    * @return API for accessing the revision.
    * @throws RestApiException if an error occurred.
    */
-  RevisionApi current() throws RestApiException;
+  default RevisionApi current() throws RestApiException {
+    return revision("current");
+  }
 
   /**
    * Look up a revision of a change by number.
    *
    * @see #current()
    */
-  RevisionApi revision(int id) throws RestApiException;
+  default RevisionApi revision(int id) throws RestApiException {
+    return revision(Integer.toString(id));
+  }
 
   /**
-   * Look up a revision of a change by commit SHA-1.
+   * Look up a revision of a change by commit SHA-1 or other supported revision string.
    *
    * @see #current()
    */
@@ -79,15 +83,23 @@
    */
   ReviewerApi reviewer(String id) throws RestApiException;
 
-  void abandon() throws RestApiException;
+  default void abandon() throws RestApiException {
+    abandon(new AbandonInput());
+  }
 
   void abandon(AbandonInput in) throws RestApiException;
 
-  void restore() throws RestApiException;
+  default void restore() throws RestApiException {
+    restore(new RestoreInput());
+  }
 
   void restore(RestoreInput in) throws RestApiException;
 
-  void move(String destination) throws RestApiException;
+  default void move(String destination) throws RestApiException {
+    MoveInput in = new MoveInput();
+    in.destinationBranch = destination;
+    move(in);
+  }
 
   void move(MoveInput in) throws RestApiException;
 
@@ -132,7 +144,9 @@
    *
    * @see Changes#id(int)
    */
-  ChangeApi revert() throws RestApiException;
+  default ChangeApi revert() throws RestApiException {
+    return revert(new RevertInput());
+  }
 
   /**
    * Create a new change that reverts this change.
@@ -144,10 +158,17 @@
   /** Create a merge patch set for the change. */
   ChangeInfo createMergePatchSet(MergePatchSetInput in) throws RestApiException;
 
-  List<ChangeInfo> submittedTogether() throws RestApiException;
+  default List<ChangeInfo> submittedTogether() throws RestApiException {
+    SubmittedTogetherInfo info =
+        submittedTogether(
+            EnumSet.noneOf(ListChangesOption.class), EnumSet.noneOf(SubmittedTogetherOption.class));
+    return info.changes;
+  }
 
-  SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
-      throws RestApiException;
+  default SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
+      throws RestApiException {
+    return submittedTogether(EnumSet.noneOf(ListChangesOption.class), options);
+  }
 
   SubmittedTogetherInfo submittedTogether(
       EnumSet<ListChangesOption> listOptions, EnumSet<SubmittedTogetherOption> submitOptions)
@@ -155,10 +176,14 @@
 
   /** Publishes a draft change. */
   @Deprecated
-  void publish() throws RestApiException;
+  default void publish() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   /** Rebase the current revision of a change using default options. */
-  void rebase() throws RestApiException;
+  default void rebase() throws RestApiException {
+    rebase(new RebaseInput());
+  }
 
   /** Rebase the current revision of a change. */
   void rebase(RebaseInput in) throws RestApiException;
@@ -172,13 +197,19 @@
 
   IncludedInInfo includedIn() throws RestApiException;
 
-  AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException;
+  default AddReviewerResult addReviewer(String reviewer) throws RestApiException {
+    AddReviewerInput in = new AddReviewerInput();
+    in.reviewer = reviewer;
+    return addReviewer(in);
+  }
 
-  AddReviewerResult addReviewer(String in) throws RestApiException;
+  AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException;
 
   SuggestedReviewersRequest suggestReviewers() throws RestApiException;
 
-  SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException;
+  default SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
+    return suggestReviewers().withQuery(query);
+  }
 
   ChangeInfo get(EnumSet<ListChangesOption> options) throws RestApiException;
 
@@ -198,10 +229,16 @@
    *   <li>{@code SKIP_MERGEABLE} is omitted, so the {@code mergeable} bit <em>is</em> set.
    * </ul>
    */
-  ChangeInfo get() throws RestApiException;
+  default ChangeInfo get() throws RestApiException {
+    return get(
+        EnumSet.complementOf(
+            EnumSet.of(ListChangesOption.CHECK, ListChangesOption.SKIP_MERGEABLE)));
+  }
 
   /** {@link #get(ListChangesOption...)} with no options included. */
-  ChangeInfo info() throws RestApiException;
+  default ChangeInfo info() throws RestApiException {
+    return get(EnumSet.noneOf(ListChangesOption.class));
+  }
 
   /**
    * Retrieve change edit when exists.
@@ -210,7 +247,9 @@
    *     ChangeEditApi#get()}.
    */
   @Deprecated
-  EditInfo getEdit() throws RestApiException;
+  default EditInfo getEdit() throws RestApiException {
+    return edit().get().orElse(null);
+  }
 
   /**
    * Provides access to an API regarding the change edit of this change.
@@ -221,7 +260,11 @@
   ChangeEditApi edit() throws RestApiException;
 
   /** Create a new patch set with a new commit message. */
-  void setMessage(String message) throws RestApiException;
+  default void setMessage(String message) throws RestApiException {
+    CommitMessageInput in = new CommitMessageInput();
+    in.message = message;
+    setMessage(in);
+  }
 
   /** Create a new patch set with a new commit message. */
   void setMessage(CommitMessageInput in) throws RestApiException;
@@ -347,16 +390,6 @@
     }
 
     @Override
-    public RevisionApi current() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public RevisionApi revision(int id) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ReviewerApi reviewer(String id) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -367,31 +400,16 @@
     }
 
     @Override
-    public void abandon() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void abandon(AbandonInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void restore() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void restore(RestoreInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void move(String destination) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void move(MoveInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -412,27 +430,11 @@
     }
 
     @Override
-    public ChangeApi revert() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeApi revert(RevertInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void publish() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Deprecated
-    @Override
-    public void rebase() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void rebase(RebaseInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -463,51 +465,21 @@
     }
 
     @Override
-    public AddReviewerResult addReviewer(String in) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public SuggestedReviewersRequest suggestReviewers() throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeInfo get(EnumSet<ListChangesOption> options) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public ChangeInfo get() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public ChangeInfo info() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public void setMessage(String message) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void setMessage(CommitMessageInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public EditInfo getEdit() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeEditApi edit() throws RestApiException {
       throw new NotImplementedException();
     }
diff --git a/java/com/google/gerrit/extensions/api/changes/RevisionApi.java b/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
index 75cf3a6..14dc589 100644
--- a/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
+++ b/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.extensions.api.changes;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ActionInfo;
 import com.google.gerrit.extensions.common.CherryPickChangeInfo;
@@ -34,7 +35,9 @@
 
 public interface RevisionApi {
   @Deprecated
-  void delete() throws RestApiException;
+  default void delete() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   String description() throws RestApiException;
 
@@ -42,22 +45,32 @@
 
   ReviewResult review(ReviewInput in) throws RestApiException;
 
-  void submit() throws RestApiException;
+  default void submit() throws RestApiException {
+    SubmitInput in = new SubmitInput();
+    submit(in);
+  }
 
   void submit(SubmitInput in) throws RestApiException;
 
-  BinaryResult submitPreview() throws RestApiException;
+  default BinaryResult submitPreview() throws RestApiException {
+    return submitPreview("zip");
+  }
 
   BinaryResult submitPreview(String format) throws RestApiException;
 
   @Deprecated
-  void publish() throws RestApiException;
+  default void publish() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   ChangeApi cherryPick(CherryPickInput in) throws RestApiException;
 
   CherryPickChangeInfo cherryPickAsInfo(CherryPickInput in) throws RestApiException;
 
-  ChangeApi rebase() throws RestApiException;
+  default ChangeApi rebase() throws RestApiException {
+    RebaseInput in = new RebaseInput();
+    return rebase(in);
+  }
 
   ChangeApi rebase(RebaseInput in) throws RestApiException;
 
@@ -69,9 +82,11 @@
 
   Set<String> reviewed() throws RestApiException;
 
-  Map<String, FileInfo> files() throws RestApiException;
+  default Map<String, FileInfo> files() throws RestApiException {
+    return files(null);
+  }
 
-  Map<String, FileInfo> files(String base) throws RestApiException;
+  Map<String, FileInfo> files(@Nullable String base) throws RestApiException;
 
   Map<String, FileInfo> files(int parentNum) throws RestApiException;
 
@@ -165,33 +180,16 @@
    * interface.
    */
   class NotImplemented implements RevisionApi {
-    @Deprecated
-    @Override
-    public void delete() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
     @Override
     public ReviewResult review(ReviewInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void submit() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void submit(SubmitInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
-    @Deprecated
-    @Override
-    public void publish() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
     @Override
     public ChangeApi cherryPick(CherryPickInput in) throws RestApiException {
       throw new NotImplementedException();
@@ -203,11 +201,6 @@
     }
 
     @Override
-    public ChangeApi rebase() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeApi rebase(RebaseInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -253,11 +246,6 @@
     }
 
     @Override
-    public Map<String, FileInfo> files() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public List<String> queryFiles(String query) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -348,11 +336,6 @@
     }
 
     @Override
-    public BinaryResult submitPreview() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public BinaryResult submitPreview(String format) throws RestApiException {
       throw new NotImplementedException();
     }
diff --git a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
index 358a3a8..0f731ed 100644
--- a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
@@ -43,7 +43,6 @@
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.CommitMessageInput;
-import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.common.Input;
 import com.google.gerrit.extensions.common.MergePatchSetInput;
 import com.google.gerrit.extensions.common.PureRevertInfo;
@@ -256,16 +255,6 @@
   }
 
   @Override
-  public RevisionApi current() throws RestApiException {
-    return revision("current");
-  }
-
-  @Override
-  public RevisionApi revision(int id) throws RestApiException {
-    return revision(String.valueOf(id));
-  }
-
-  @Override
   public RevisionApi revision(String id) throws RestApiException {
     try {
       return revisionApi.create(revisions.parse(change, IdString.fromDecoded(id)));
@@ -284,11 +273,6 @@
   }
 
   @Override
-  public void abandon() throws RestApiException {
-    abandon(new AbandonInput());
-  }
-
-  @Override
   public void abandon(AbandonInput in) throws RestApiException {
     try {
       abandon.apply(change, in);
@@ -298,11 +282,6 @@
   }
 
   @Override
-  public void restore() throws RestApiException {
-    restore(new RestoreInput());
-  }
-
-  @Override
   public void restore(RestoreInput in) throws RestApiException {
     try {
       restore.apply(change, in);
@@ -312,13 +291,6 @@
   }
 
   @Override
-  public void move(String destination) throws RestApiException {
-    MoveInput in = new MoveInput();
-    in.destinationBranch = destination;
-    move(in);
-  }
-
-  @Override
   public void move(MoveInput in) throws RestApiException {
     try {
       move.apply(change, in);
@@ -360,11 +332,6 @@
   }
 
   @Override
-  public ChangeApi revert() throws RestApiException {
-    return revert(new RevertInput());
-  }
-
-  @Override
   public ChangeApi revert(RevertInput in) throws RestApiException {
     try {
       return changeApi.id(revert.apply(change, in)._number);
@@ -383,20 +350,6 @@
   }
 
   @Override
-  public List<ChangeInfo> submittedTogether() throws RestApiException {
-    SubmittedTogetherInfo info =
-        submittedTogether(
-            EnumSet.noneOf(ListChangesOption.class), EnumSet.noneOf(SubmittedTogetherOption.class));
-    return info.changes;
-  }
-
-  @Override
-  public SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
-      throws RestApiException {
-    return submittedTogether(EnumSet.noneOf(ListChangesOption.class), options);
-  }
-
-  @Override
   public SubmittedTogetherInfo submittedTogether(
       EnumSet<ListChangesOption> listOptions, EnumSet<SubmittedTogetherOption> submitOptions)
       throws RestApiException {
@@ -411,17 +364,6 @@
     }
   }
 
-  @Deprecated
-  @Override
-  public void publish() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public void rebase() throws RestApiException {
-    rebase(new RebaseInput());
-  }
-
   @Override
   public void rebase(RebaseInput in) throws RestApiException {
     try {
@@ -466,13 +408,6 @@
   }
 
   @Override
-  public AddReviewerResult addReviewer(String reviewer) throws RestApiException {
-    AddReviewerInput in = new AddReviewerInput();
-    in.reviewer = reviewer;
-    return addReviewer(in);
-  }
-
-  @Override
   public AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException {
     try {
       return postReviewers.apply(change, in);
@@ -491,11 +426,6 @@
     };
   }
 
-  @Override
-  public SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
-    return suggestReviewers().withQuery(query);
-  }
-
   private List<SuggestedReviewerInfo> suggestReviewers(SuggestedReviewersRequest r)
       throws RestApiException {
     try {
@@ -517,30 +447,11 @@
   }
 
   @Override
-  public ChangeInfo get() throws RestApiException {
-    return get(
-        EnumSet.complementOf(
-            EnumSet.of(ListChangesOption.CHECK, ListChangesOption.SKIP_MERGEABLE)));
-  }
-
-  @Override
-  public EditInfo getEdit() throws RestApiException {
-    return edit().get().orElse(null);
-  }
-
-  @Override
   public ChangeEditApi edit() throws RestApiException {
     return changeEditApi.create(change);
   }
 
   @Override
-  public void setMessage(String msg) throws RestApiException {
-    CommitMessageInput in = new CommitMessageInput();
-    in.message = msg;
-    setMessage(in);
-  }
-
-  @Override
   public void setMessage(CommitMessageInput in) throws RestApiException {
     try {
       putMessage.apply(change, in);
@@ -550,11 +461,6 @@
   }
 
   @Override
-  public ChangeInfo info() throws RestApiException {
-    return get(EnumSet.noneOf(ListChangesOption.class));
-  }
-
-  @Override
   public void setHashtags(HashtagsInput input) throws RestApiException {
     try {
       postHashtags.apply(change, input);
diff --git a/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java b/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
index 3f03b57..f8a2ecb 100644
--- a/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
@@ -18,6 +18,7 @@
 import static com.google.gerrit.server.api.ApiUtil.asRestApiException;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.api.changes.ChangeApi;
 import com.google.gerrit.extensions.api.changes.Changes;
 import com.google.gerrit.extensions.api.changes.CherryPickInput;
@@ -227,12 +228,6 @@
   }
 
   @Override
-  public void submit() throws RestApiException {
-    SubmitInput in = new SubmitInput();
-    submit(in);
-  }
-
-  @Override
   public void submit(SubmitInput in) throws RestApiException {
     try {
       submit.apply(revision, in);
@@ -242,11 +237,6 @@
   }
 
   @Override
-  public BinaryResult submitPreview() throws RestApiException {
-    return submitPreview("zip");
-  }
-
-  @Override
   public BinaryResult submitPreview(String format) throws RestApiException {
     try {
       submitPreview.setFormat(format);
@@ -257,22 +247,6 @@
   }
 
   @Override
-  public void publish() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public void delete() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public ChangeApi rebase() throws RestApiException {
-    RebaseInput in = new RebaseInput();
-    return rebase(in);
-  }
-
-  @Override
   public ChangeApi rebase(RebaseInput in) throws RestApiException {
     try {
       return changes.id(rebase.apply(revision, in)._number);
@@ -366,17 +340,7 @@
 
   @SuppressWarnings("unchecked")
   @Override
-  public Map<String, FileInfo> files() throws RestApiException {
-    try {
-      return (Map<String, FileInfo>) listFiles.apply(revision).value();
-    } catch (Exception e) {
-      throw asRestApiException("Cannot retrieve files", e);
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  @Override
-  public Map<String, FileInfo> files(String base) throws RestApiException {
+  public Map<String, FileInfo> files(@Nullable String base) throws RestApiException {
     try {
       return (Map<String, FileInfo>) listFiles.setBase(base).apply(revision).value();
     } catch (Exception e) {
diff --git a/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java b/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
index ef5e65b..be8fcdb 100644
--- a/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
+++ b/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
@@ -14,8 +14,11 @@
 
 package com.google.gerrit.server.git;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
+import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
@@ -28,7 +31,6 @@
  * implements {@link org.eclipse.jgit.transport.AdvertiseRefsHook}.
  */
 public class DefaultAdvertiseRefsHook extends AbstractAdvertiseRefsHook {
-
   private final PermissionBackend.ForProject perm;
   private final PermissionBackend.RefFilterOptions opts;
 
@@ -42,9 +44,24 @@
   protected Map<String, Ref> getAdvertisedRefs(Repository repo, RevWalk revWalk)
       throws ServiceMayNotContinueException {
     try {
-      return perm.filter(repo.getAllRefs(), repo, opts);
-    } catch (PermissionBackendException e) {
-      throw new ServiceMayNotContinueException(e);
+      Map<String, Ref> refs;
+      List<String> prefixes = opts.prefixes();
+      if (prefixes.isEmpty() || prefixes.get(0).isEmpty()) {
+        refs = repo.getAllRefs();
+      } else {
+        ImmutableMap.Builder<String, Ref> b = new ImmutableMap.Builder<>();
+        for (String prefix : prefixes) {
+          for (Ref ref : repo.getRefDatabase().getRefsByPrefix(prefix)) {
+            b.put(ref.getName(), ref);
+          }
+        }
+        refs = b.build();
+      }
+      return perm.filter(refs, repo, opts);
+    } catch (IOException | PermissionBackendException e) {
+      ServiceMayNotContinueException ex = new ServiceMayNotContinueException();
+      ex.initCause(e);
+      throw ex;
     }
   }
 }
diff --git a/java/com/google/gerrit/server/permissions/PermissionBackend.java b/java/com/google/gerrit/server/permissions/PermissionBackend.java
index db3c961..bea760c 100644
--- a/java/com/google/gerrit/server/permissions/PermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/PermissionBackend.java
@@ -18,6 +18,7 @@
 import static java.util.stream.Collectors.toSet;
 
 import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Sets;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.LabelType;
@@ -40,6 +41,7 @@
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
@@ -367,12 +369,19 @@
     /** Separately add reachable tags. */
     public abstract boolean filterTagsSeparately();
 
+    /**
+     * Select only refs with names matching prefixes per {@link
+     * org.eclipse.jgit.lib.RefDatabase#getRefsByPrefix}.
+     */
+    public abstract ImmutableList<String> prefixes();
+
     public abstract Builder toBuilder();
 
     public static Builder builder() {
       return new AutoValue_PermissionBackend_RefFilterOptions.Builder()
           .setFilterMeta(false)
-          .setFilterTagsSeparately(false);
+          .setFilterTagsSeparately(false)
+          .setPrefixes(Collections.singletonList(""));
     }
 
     @AutoValue.Builder
@@ -381,6 +390,8 @@
 
       public abstract Builder setFilterTagsSeparately(boolean val);
 
+      public abstract Builder setPrefixes(List<String> prefixes);
+
       public abstract RefFilterOptions build();
     }
 
diff --git a/java/com/google/gerrit/server/restapi/change/Files.java b/java/com/google/gerrit/server/restapi/change/Files.java
index 1bb6bf2..b374fdc 100644
--- a/java/com/google/gerrit/server/restapi/change/Files.java
+++ b/java/com/google/gerrit/server/restapi/change/Files.java
@@ -18,6 +18,7 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
@@ -332,7 +333,7 @@
       return this;
     }
 
-    public ListFiles setBase(String base) {
+    public ListFiles setBase(@Nullable String base) {
       this.base = base;
       return this;
     }
diff --git a/java/com/google/gerrit/server/restapi/change/QueryChanges.java b/java/com/google/gerrit/server/restapi/change/QueryChanges.java
index 4a145bc..d1eea44 100644
--- a/java/com/google/gerrit/server/restapi/change/QueryChanges.java
+++ b/java/com/google/gerrit/server/restapi/change/QueryChanges.java
@@ -82,6 +82,7 @@
     imp.setStart(start);
   }
 
+  @Override
   public void setDynamicBean(String plugin, DynamicOptions.DynamicBean dynamicBean) {
     imp.setDynamicBean(plugin, dynamicBean);
   }
diff --git a/java/com/google/gerrit/sshd/commands/Query.java b/java/com/google/gerrit/sshd/commands/Query.java
index c4a21d1..4d8351e 100644
--- a/java/com/google/gerrit/sshd/commands/Query.java
+++ b/java/com/google/gerrit/sshd/commands/Query.java
@@ -104,6 +104,7 @@
     processor.query(join(query, " "));
   }
 
+  @Override
   public void setDynamicBean(String plugin, DynamicOptions.DynamicBean dynamicBean) {
     processor.setDynamicBean(plugin, dynamicBean);
   }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index ed4137d..30aef73 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -1692,7 +1692,7 @@
     PushOneCommit.Result result = createChange();
 
     String username = name("new-user");
-    gApi.accounts().create(username).setActive(false);
+    accountOperations.newAccount().username(username).inactive().create();
 
     AddReviewerInput in = new AddReviewerInput();
     in.reviewer = username;
@@ -1714,7 +1714,7 @@
     PushOneCommit.Result result = createChange();
 
     String username = "user@domain.com";
-    gApi.accounts().create(username).setActive(false);
+    accountOperations.newAccount().username(username).inactive().create();
 
     AddReviewerInput in = new AddReviewerInput();
     in.reviewer = username;
@@ -2096,7 +2096,7 @@
     ChangeResource rsrc = parseResource(r);
     String oldETag = rsrc.getETag();
 
-    gApi.accounts().id(admin.id.get()).setStatus("new status");
+    accountOperations.account(admin.id).forUpdate().status("new status").update();
     rsrc = parseResource(r);
     assertThat(rsrc.getETag()).isNotEqualTo(oldETag);
   }
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
index 9ff2c05..b8380f5 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.common.collect.Iterables;
+import com.google.gerrit.acceptance.testsuite.account.AccountOperations;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
@@ -33,6 +34,7 @@
 
 public class MailProcessorIT extends AbstractMailIT {
   @Inject private MailProcessor mailProcessor;
+  @Inject private AccountOperations accountOperations;
 
   @Test
   public void parseAndPersistChangeMessage() throws Exception {
@@ -163,16 +165,13 @@
     b.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
     // Set account state to inactive
-    gApi.accounts().id("user").setActive(false);
+    accountOperations.account(user.id).forUpdate().inactive().update();
 
     mailProcessor.process(b.build());
     comments = gApi.changes().id(changeId).current().commentsAsList();
 
     // Check that comment size has not changed
     assertThat(comments).hasSize(2);
-
-    // Reset
-    gApi.accounts().id("user").setActive(true);
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
index bb545c9..93e97c4 100644
--- a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
+++ b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
@@ -45,13 +45,13 @@
       case V2_4:
         return "elasticsearch:2.4.6-alpine";
       case V5_6:
-        return "docker.elastic.co/elasticsearch/elasticsearch:5.6.12";
+        return "docker.elastic.co/elasticsearch/elasticsearch:5.6.13";
       case V6_2:
         return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.2.4";
       case V6_3:
         return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.3.2";
       case V6_4:
-        return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.4.2";
+        return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.4.3";
     }
     throw new IllegalStateException("No tests for version: " + version.name());
   }
diff --git a/lib/httpcomponents/BUILD b/lib/httpcomponents/BUILD
index 8e9fbc5..a875eaf 100644
--- a/lib/httpcomponents/BUILD
+++ b/lib/httpcomponents/BUILD
@@ -28,20 +28,15 @@
 )
 
 java_library(
-    name = "httpmime",
-    data = ["//lib:LICENSE-Apache2.0"],
-    visibility = ["//visibility:public"],
-    exports = ["@httpmime//jar"],
-)
-
-java_library(
     name = "httpasyncclient",
     data = ["//lib:LICENSE-Apache2.0"],
+    visibility = ["//java/com/google/gerrit/elasticsearch:__pkg__"],
     exports = ["@httpasyncclient//jar"],
 )
 
 java_library(
     name = "httpcore-nio",
     data = ["//lib:LICENSE-Apache2.0"],
+    visibility = ["//java/com/google/gerrit/elasticsearch:__pkg__"],
     exports = ["@httpcore-nio//jar"],
 )
diff --git a/plugins/replication b/plugins/replication
index a7b900b..bc5efb5 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit a7b900bd524c333c8ca2825e37fa781ac055ac36
+Subproject commit bc5efb5b60a5a93c25c075f3667841e02532a99c
diff --git a/plugins/singleusergroup b/plugins/singleusergroup
index cc636d7..0f798f6 160000
--- a/plugins/singleusergroup
+++ b/plugins/singleusergroup
@@ -1 +1 @@
-Subproject commit cc636d7e36afb62455a9f045b125d246fd84afd0
+Subproject commit 0f798f61c0c598c1499cbaacc1c609078c8bf0d5
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
index 148cd34..38f5f2f 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
@@ -531,6 +531,7 @@
             patch-num="{{_patchRange.patchNum}}"
             base-patch-num="{{_patchRange.basePatchNum}}"
             files-expanded="[[_filesExpanded]]"
+            diff-prefs-disabled="[[_diffPrefsDisabled]]"
             on-open-diff-prefs="_handleOpenDiffPrefs"
             on-open-download-dialog="_handleOpenDownloadDialog"
             on-open-upload-help-dialog="_handleOpenUploadHelpDialog"
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index a905c9f..24453be 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -108,6 +108,14 @@
         type: Boolean,
         value: false,
       },
+      disableDiffPrefs: {
+        type: Boolean,
+        value: false,
+      },
+      _diffPrefsDisabled: {
+        type: Boolean,
+        computed: '_computeDiffPrefsDisabled(disableDiffPrefs, _loggedIn)',
+      },
       _commentThreads: Array,
       /** @type {?} */
       _serverConfig: {
@@ -978,6 +986,8 @@
       if (this.shouldSuppressKeyboardShortcut(e) ||
           this.modifierPressed(e)) { return; }
 
+      if (this._diffPrefsDisabled) { return; }
+
       e.preventDefault();
       this.$.fileList.openDiffPrefs();
     },
@@ -1664,5 +1674,9 @@
     _computeCurrentRevision(currentRevision, revisions) {
       return revisions && revisions[currentRevision];
     },
+
+    _computeDiffPrefsDisabled(disableDiffPrefs, loggedIn) {
+      return disableDiffPrefs || !loggedIn;
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index 4b6cc6c..df06e55 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -291,6 +291,16 @@
 
       test(', should open diff preferences', () => {
         const stub = sandbox.stub(element.$.fileList.$.diffPreferences, 'open');
+        element._loggedIn = false;
+        element.disableDiffPrefs = true;
+        MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+        assert.isFalse(stub.called);
+
+        element._loggedIn = true;
+        MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+        assert.isFalse(stub.called);
+
+        element.disableDiffPrefs = false;
         MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
         assert.isTrue(stub.called);
       });
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
index 142e706..924ddab 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
@@ -249,10 +249,10 @@
           <gr-diff-mode-selector
               id="modeSelect"
               mode="{{diffViewMode}}"
-              save-on-change="[[loggedIn]]"></gr-diff-mode-selector>
+              save-on-change="[[!diffPrefsDisabled]]"></gr-diff-mode-selector>
           <span id="diffPrefsContainer"
               class="hideOnEdit"
-              hidden$="[[_computePrefsButtonHidden(diffPrefs, loggedIn)]]"
+              hidden$="[[_computePrefsButtonHidden(diffPrefs, diffPrefsDisabled)]]"
               hidden>
             <gr-button
                 link
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
index 665472b..b9e6288 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
@@ -62,6 +62,7 @@
       serverConfig: Object,
       shownFileCount: Number,
       diffPrefs: Object,
+      diffPrefsDisabled: Boolean,
       diffViewMode: {
         type: String,
         notify: true,
@@ -186,11 +187,10 @@
           });
     },
 
-    _computePrefsButtonHidden(prefs, loggedIn) {
-      return !loggedIn || !prefs;
+    _computePrefsButtonHidden(prefs, diffPrefsDisabled) {
+      return diffPrefsDisabled || !prefs;
     },
 
-
     _fileListActionsVisible(shownFileCount, maxFilesForBulkActions) {
       return shownFileCount <= maxFilesForBulkActions;
     },
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
index e2685e1..adfeeb4 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
@@ -62,21 +62,21 @@
       });
     });
 
-    test('Diff preferences hidden when no prefs or logged out', () => {
-      element.loggedIn = false;
+    test('Diff preferences hidden when no prefs or diffPrefsDisabled', () => {
+      element.diffPrefsDisabled = true;
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = true;
+      element.diffPrefsDisabled = false;
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = false;
+      element.diffPrefsDisabled = true;
       element.diffPrefs = {font_size: '12'};
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = true;
+      element.diffPrefsDisabled = false;
       flushAsynchronousOperations();
       assert.isFalse(element.$.diffPrefsContainer.hidden);
     });
@@ -265,7 +265,7 @@
 
     suite('editMode behavior', () => {
       setup(() => {
-        element.loggedIn = true;
+        element.diffPrefsDisabled = false;
         element.diffPrefs = {};
       });
 
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
index ff5b290..f2cfe87 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
@@ -290,14 +290,14 @@
     _resultsChanged(related, submittedTogether, conflicts,
         cherryPicks, sameTopic) {
       const results = [
-        related,
-        submittedTogether,
+        related && related.changes,
+        submittedTogether && submittedTogether.changes,
         conflicts,
         cherryPicks,
         sameTopic,
       ];
       for (let i = 0; i < results.length; i++) {
-        if (results[i].length > 0) {
+        if (results[i] && results[i].length > 0) {
           this.hidden = false;
           this.fire('update', null, {bubbles: false});
           return;
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.html b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.html
index bfeb694..48cc565 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.html
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.html
@@ -382,7 +382,7 @@
           true);
     });
 
-    test('clear and empties', () => {
+    suite('hidden attribute and update event', () => {
       const changes = [{
         project: 'foo/bar',
         change_id: 'Ideadbeef',
@@ -397,33 +397,68 @@
         _current_revision_number: 1,
         status: 'NEW',
       }];
-      element._relatedResponse = {changes};
-      element._submittedTogether = {changes};
-      element._conflicts = changes;
-      element._cherryPicks = changes;
-      element._sameTopic = changes;
 
-      element.hidden = false;
-      element.clear();
-      assert.isTrue(element.hidden);
-      assert.equal(element._relatedResponse.changes.length, 0);
-      assert.equal(element._submittedTogether.changes.length, 0);
-      assert.equal(element._conflicts.length, 0);
-      assert.equal(element._cherryPicks.length, 0);
-      assert.equal(element._sameTopic.length, 0);
-    });
+      test('clear and empties', () => {
+        element._relatedResponse = {changes};
+        element._submittedTogether = {changes};
+        element._conflicts = changes;
+        element._cherryPicks = changes;
+        element._sameTopic = changes;
 
-    test('update fires', () => {
-      const updateHandler = sandbox.stub();
-      element.addEventListener('update', updateHandler);
+        element.hidden = false;
+        element.clear();
+        assert.isTrue(element.hidden);
+        assert.equal(element._relatedResponse.changes.length, 0);
+        assert.equal(element._submittedTogether.changes.length, 0);
+        assert.equal(element._conflicts.length, 0);
+        assert.equal(element._cherryPicks.length, 0);
+        assert.equal(element._sameTopic.length, 0);
+      });
 
-      element._resultsChanged([], [], [], [], []);
-      assert.isTrue(element.hidden);
-      assert.isFalse(updateHandler.called);
+      test('update fires', () => {
+        const updateHandler = sandbox.stub();
+        element.addEventListener('update', updateHandler);
 
-      element._resultsChanged([], [], [], [], ['test']);
-      assert.isFalse(element.hidden);
-      assert.isTrue(updateHandler.called);
+        element._resultsChanged({}, {}, [], [], []);
+        assert.isTrue(element.hidden);
+        assert.isFalse(updateHandler.called);
+
+        element._resultsChanged({}, {}, [], [], ['test']);
+        assert.isFalse(element.hidden);
+        assert.isTrue(updateHandler.called);
+      });
+
+      suite('hiding and unhiding', () => {
+        test('related response', () => {
+          assert.isTrue(element.hidden);
+          element._resultsChanged({changes}, {}, [], [], []);
+          assert.isFalse(element.hidden);
+        });
+
+        test('submitted together', () => {
+          assert.isTrue(element.hidden);
+          element._resultsChanged({}, {changes}, [], [], []);
+          assert.isFalse(element.hidden);
+        });
+
+        test('conflicts', () => {
+          assert.isTrue(element.hidden);
+          element._resultsChanged({}, {}, changes, [], []);
+          assert.isFalse(element.hidden);
+        });
+
+        test('cherrypicks', () => {
+          assert.isTrue(element.hidden);
+          element._resultsChanged({}, {}, [], changes, []);
+          assert.isFalse(element.hidden);
+        });
+
+        test('same topic', () => {
+          assert.isTrue(element.hidden);
+          element._resultsChanged({}, {}, [], [], changes);
+          assert.isFalse(element.hidden);
+        });
+      });
     });
 
     test('_computeChangeURL uses Gerrit.Nav', () => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
index 6ea0330..72c7285 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
@@ -91,10 +91,12 @@
         text-align: right;
         white-space: nowrap;
       }
-      a.date:link,
-      a.date:visited {
+      span.date {
         color: var(--deemphasized-text-color);
       }
+      span.date:hover {
+        text-decoration: underline;
+      }
       .actions {
         display: flex;
         justify-content: flex-end;
@@ -255,11 +257,11 @@
             on-tap="_handleCommentDelete">
           (Delete)
         </gr-button>
-        <a class="date" href$="[[_computeLinkToComment(comment)]]" on-tap="_handleLinkTap">
+        <span class="date" on-tap="_handleAnchorTap">
           <gr-date-formatter
               has-tooltip
               date-str="[[comment.updated]]"></gr-date-formatter>
-        </a>
+        </span>
         <div class="show-hide">
           <label class="show-hide">
             <input type="checkbox" class="show-hide"
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
index 90d465f..5165db0 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
@@ -29,6 +29,8 @@
   const REPORT_UPDATE_DRAFT = 'UpdateDraftComment';
   const REPORT_DISCARD_DRAFT = 'DiscardDraftComment';
 
+  const FILE = 'FILE';
+
   Polymer({
     is: 'gr-diff-comment',
 
@@ -64,6 +66,12 @@
      * @event comment-mouse-out
      */
 
+    /**
+     * Fired when the comment's timestamp is tapped.
+     *
+     * @event comment-anchor-tap
+     */
+
     properties: {
       changeNum: String,
       /** @type {?} */
@@ -333,10 +341,6 @@
       }
     },
 
-    _computeLinkToComment(comment) {
-      return '#' + comment.line;
-    },
-
     _computeDeleteButtonClass(isAdmin, draft) {
       return isAdmin && !draft ? 'showDeleteButtons' : '';
     },
@@ -401,15 +405,16 @@
       }, STORAGE_DEBOUNCE_INTERVAL);
     },
 
-    _handleLinkTap(e) {
+    _handleAnchorTap(e) {
       e.preventDefault();
-      const hash = this._computeLinkToComment(this.comment);
-      // Don't add the hash to the window history if it's already there.
-      // Otherwise you mess up expected back button behavior.
-      if (window.location.hash == hash) { return; }
-      // Change the URL but don’t trigger a nav event. Otherwise it will
-      // reload the page.
-      page.show(window.location.pathname + hash, null, false);
+      if (!this.comment.line) { return; }
+      this.dispatchEvent(new CustomEvent('comment-anchor-tap', {
+        bubbles: true,
+        detail: {
+          number: this.comment.line || FILE,
+          side: this.side,
+        },
+      }));
     },
 
     _handleEdit(e) {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
index ca85892..912e615 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
@@ -99,15 +99,17 @@
           'header middle content is not visible');
     });
 
-    test('clicking on date link does not trigger nav', () => {
-      const showStub = sinon.stub(page, 'show');
+    test('clicking on date link fires event', () => {
+      element.side = 'PARENT';
+      const stub = sinon.stub();
+      element.addEventListener('comment-anchor-tap', stub);
       const dateEl = element.$$('.date');
       assert.ok(dateEl);
       MockInteractions.tap(dateEl);
-      const dest = window.location.pathname + '#5';
-      assert(showStub.lastCall.calledWithExactly(dest, null, false),
-          'Should navigate to ' + dest + ' without triggering nav');
-      showStub.restore();
+
+      assert.isTrue(stub.called);
+      assert.deepEqual(stub.lastCall.args[0].detail,
+          {side: element.side, number: element.comment.line});
     });
 
     test('message is not retrieved from storage when other edits', done => {
@@ -733,17 +735,6 @@
       assert.isTrue(saveStub.calledOnce);
     });
 
-    test('clicking on date link does not trigger nav', () => {
-      const showStub = sinon.stub(page, 'show');
-      const dateEl = element.$$('.date');
-      assert.ok(dateEl);
-      MockInteractions.tap(dateEl);
-      const dest = window.location.pathname + '#5';
-      assert(showStub.lastCall.calledWithExactly(dest, null, false),
-          'Should navigate to ' + dest + ' without triggering nav');
-      showStub.restore();
-    });
-
     test('proper event fires on resolve, comment is not saved', done => {
       const save = sandbox.stub(element, 'save');
       element.addEventListener('comment-update', e => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
index 0866849..8acbd5d 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
@@ -286,11 +286,11 @@
             <span>Diff view:</span>
             <gr-diff-mode-selector
                 id="modeSelect"
-                save-on-change="[[_loggedIn]]"
+                save-on-change="[[!_diffPrefsDisabled]]"
                 mode="{{changeViewState.diffMode}}"></gr-diff-mode-selector>
           </div>
           <span id="diffPrefsContainer"
-              hidden$="[[_computePrefsButtonHidden(_prefs, _loggedIn)]]" hidden>
+              hidden$="[[_computePrefsButtonHidden(_prefs, _diffPrefsDisabled)]]" hidden>
             <span class="preferences desktop">
               <gr-button
                   link
@@ -336,6 +336,7 @@
         project-name="[[_change.project]]"
         view-mode="[[_diffMode]]"
         is-blame-loaded="{{_isBlameLoaded}}"
+        on-comment-anchor-tap="_onLineSelected"
         on-line-selected="_onLineSelected">
     </gr-diff-host>
     <gr-diff-preferences
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
index 6f361d8..59c5b1f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
@@ -69,6 +69,14 @@
         value() { return {}; },
         observer: '_changeViewStateChanged',
       },
+      disableDiffPrefs: {
+        type: Boolean,
+        value: false,
+      },
+      _diffPrefsDisabled: {
+        type: Boolean,
+        computed: '_computeDiffPrefsDisabled(disableDiffPrefs, _loggedIn)',
+      },
       /** @type {?} */
       _patchRange: Object,
       /** @type {?} */
@@ -450,6 +458,7 @@
     _handleCommaKey(e) {
       if (this.shouldSuppressKeyboardShortcut(e) ||
           this.modifierPressed(e)) { return; }
+      if (this._diffPrefsDisabled) { return; }
 
       e.preventDefault();
       this.$.diffPreferences.open();
@@ -791,8 +800,8 @@
           (unresolvedString ? `${unresolvedString}` : '');
     },
 
-    _computePrefsButtonHidden(prefs, loggedIn) {
-      return !loggedIn || !prefs;
+    _computePrefsButtonHidden(prefs, prefsDisabled) {
+      return prefsDisabled || !prefs;
     },
 
     _handleFileChange(e) {
@@ -1012,5 +1021,9 @@
       if (this.shouldSuppressKeyboardShortcut(e)) { return; }
       this.$.diffHost.expandAllContext();
     },
+
+    _computeDiffPrefsDisabled(disableDiffPrefs, loggedIn) {
+      return disableDiffPrefs || !loggedIn;
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
index 431578b..3a5ca51 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
@@ -135,6 +135,7 @@
       element._fileList = ['chell.go', 'glados.txt', 'wheatley.md'];
       element._path = 'glados.txt';
       element.changeViewState.selectedFileIndex = 1;
+      element._loggedIn = true;
 
       const diffNavStub = sandbox.stub(Gerrit.Nav, 'navigateToDiff');
       const changeNavStub = sandbox.stub(Gerrit.Nav, 'navigateToChange');
@@ -177,6 +178,10 @@
       MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
       assert(showPrefsStub.calledOnce);
 
+      element.disableDiffPrefs = true;
+      MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+      assert(showPrefsStub.calledOnce);
+
       let scrollStub = sandbox.stub(element.$.cursor, 'moveToNextChunk');
       MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
       assert(scrollStub.calledOnce);
@@ -343,23 +348,39 @@
           PARENT), 'Should navigate to /c/42/1');
     });
 
-    test('Diff preferences hidden when no prefs or logged out', () => {
-      element._loggedIn = false;
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+    suite('diff prefs hidden', () => {
+      test('when no prefs or logged out', () => {
+        element.disableDiffPrefs = false;
+        element._loggedIn = false;
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = true;
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = true;
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = false;
-      element._prefs = {font_size: '12'};
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = false;
+        element._prefs = {font_size: '12'};
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = true;
-      flushAsynchronousOperations();
-      assert.isFalse(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = true;
+        flushAsynchronousOperations();
+        assert.isFalse(element.$.diffPrefsContainer.hidden);
+      });
+
+      test('when disableDiffPrefs is set', () => {
+        element._loggedIn = true;
+        element._prefs = {font_size: '12'};
+        element.disableDiffPrefs = false;
+        flushAsynchronousOperations();
+
+        assert.isFalse(element.$.diffPrefsContainer.hidden);
+        element.disableDiffPrefs = true;
+        flushAsynchronousOperations();
+
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
+      });
     });
 
     test('prefsButton opens gr-diff-preferences', () => {
diff --git a/tools/BUILD b/tools/BUILD
index c368eed..aefb867 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -13,7 +13,7 @@
 
 default_java_toolchain(
     name = "error_prone_warnings_toolchain",
-    bootclasspath = ["@bazel_tools//tools/jdk:platformclasspath9.jar"],
+    bootclasspath = ["@bazel_tools//tools/jdk:platformclasspath.jar"],
     jvm_opts = JDK9_JVM_OPTS,
     package_configuration = [
         ":error_prone",