diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/AlphaUploadBuilder.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/AlphaUploadBuilder.java
index c0fd869a0..d7f0bf393 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/AlphaUploadBuilder.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/AlphaUploadBuilder.java
@@ -155,7 +155,8 @@ public AlphaUploadBuilder withStrictConflict(Boolean strictConflict) {
      *
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/DbxUserFilesRequests.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/DbxUserFilesRequests.java
index 764bad73f..a183dcd56 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/DbxUserFilesRequests.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/DbxUserFilesRequests.java
@@ -4103,10 +4103,11 @@ public UploadSessionAppendBatchUploader uploadSessionAppendBatch(List<UploadSess
      * @param entries  Append information for each file in the batch. Must
      *     contain at most 500 items, not contain a {@code null} item, and not
      *     be {@code null}.
-     * @param contentHash  A hash of the entire request body which is all the
-     *     concatenated pieces of file content that were uploaded in this call.
-     *     If provided and the uploaded content does not match this hash, an
-     *     error will be returned. For more information see our <a
+     * @param contentHash  A single hash of all the concatenated file contents
+     *     uploaded in this call. If provided and the uploaded content does not
+     *     match this hash, an error will be returned. Optional, but recommended
+     *     to avoid committing data corrupted in transit. For more information
+     *     see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
@@ -4196,7 +4197,8 @@ public UploadSessionFinishUploader uploadSessionFinish(UploadSessionCursor curso
      *     commit. Must not be {@code null}.
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadArg.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadArg.java
index 9b07e72de..517cf1f27 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadArg.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadArg.java
@@ -63,7 +63,8 @@ class UploadArg extends CommitInfo {
      *     the target path refers to a file with identical contents.
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
@@ -187,8 +188,9 @@ public boolean getStrictConflict() {
 
     /**
      * A hash of the file content uploaded in this call. If provided and the
-     * uploaded content does not match this hash, an error will be returned. For
-     * more information see our <a
+     * uploaded content does not match this hash, an error will be returned.
+     * Optional, but recommended to avoid committing data corrupted in transit.
+     * For more information see our <a
      * href="https://www.dropbox.com/developers/reference/content-hash">Content
      * hash</a> page.
      *
@@ -233,7 +235,9 @@ protected Builder(String path) {
          *
          * @param contentHash  A hash of the file content uploaded in this call.
          *     If provided and the uploaded content does not match this hash, an
-         *     error will be returned. For more information see our <a
+         *     error will be returned. Optional, but recommended to avoid
+         *     committing data corrupted in transit. For more information see
+         *     our <a
          *     href="https://www.dropbox.com/developers/reference/content-hash">Content
          *     hash</a> page. Must have length of at least 64 and have length of
          *     at most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadBuilder.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadBuilder.java
index 976ce921d..aec500bba 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadBuilder.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadBuilder.java
@@ -154,7 +154,8 @@ public UploadBuilder withStrictConflict(Boolean strictConflict) {
      *
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendArg.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendArg.java
index d2e507fb9..9beaf28fb 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendArg.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendArg.java
@@ -40,7 +40,8 @@ class UploadSessionAppendArg {
      *     anymore with the current session.
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
@@ -105,8 +106,9 @@ public boolean getClose() {
 
     /**
      * A hash of the file content uploaded in this call. If provided and the
-     * uploaded content does not match this hash, an error will be returned. For
-     * more information see our <a
+     * uploaded content does not match this hash, an error will be returned.
+     * Optional, but recommended to avoid committing data corrupted in transit.
+     * For more information see our <a
      * href="https://www.dropbox.com/developers/reference/content-hash">Content
      * hash</a> page.
      *
@@ -179,7 +181,9 @@ public Builder withClose(Boolean close) {
          *
          * @param contentHash  A hash of the file content uploaded in this call.
          *     If provided and the uploaded content does not match this hash, an
-         *     error will be returned. For more information see our <a
+         *     error will be returned. Optional, but recommended to avoid
+         *     committing data corrupted in transit. For more information see
+         *     our <a
          *     href="https://www.dropbox.com/developers/reference/content-hash">Content
          *     hash</a> page. Must have length of at least 64 and have length of
          *     at most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendV2Builder.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendV2Builder.java
index 9cd676f22..e7a913ca8 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendV2Builder.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionAppendV2Builder.java
@@ -60,7 +60,8 @@ public UploadSessionAppendV2Builder withClose(Boolean close) {
      *
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionFinishArg.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionFinishArg.java
index 936041075..b96072cf9 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionFinishArg.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionFinishArg.java
@@ -37,7 +37,8 @@ public class UploadSessionFinishArg {
      *     commit. Must not be {@code null}.
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
@@ -104,8 +105,9 @@ public CommitInfo getCommit() {
 
     /**
      * A hash of the file content uploaded in this call. If provided and the
-     * uploaded content does not match this hash, an error will be returned. For
-     * more information see our <a
+     * uploaded content does not match this hash, an error will be returned.
+     * Optional, but recommended to avoid committing data corrupted in transit.
+     * For more information see our <a
      * href="https://www.dropbox.com/developers/reference/content-hash">Content
      * hash</a> page.
      *
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartArg.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartArg.java
index 20fcc0195..7d652b0f2 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartArg.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartArg.java
@@ -40,7 +40,8 @@ class UploadSessionStartArg {
      *     specified, default is {@link UploadSessionType#SEQUENTIAL}.
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
@@ -97,8 +98,9 @@ public UploadSessionType getSessionType() {
 
     /**
      * A hash of the file content uploaded in this call. If provided and the
-     * uploaded content does not match this hash, an error will be returned. For
-     * more information see our <a
+     * uploaded content does not match this hash, an error will be returned.
+     * Optional, but recommended to avoid committing data corrupted in transit.
+     * For more information see our <a
      * href="https://www.dropbox.com/developers/reference/content-hash">Content
      * hash</a> page.
      *
@@ -175,7 +177,9 @@ public Builder withSessionType(UploadSessionType sessionType) {
          *
          * @param contentHash  A hash of the file content uploaded in this call.
          *     If provided and the uploaded content does not match this hash, an
-         *     error will be returned. For more information see our <a
+         *     error will be returned. Optional, but recommended to avoid
+         *     committing data corrupted in transit. For more information see
+         *     our <a
          *     href="https://www.dropbox.com/developers/reference/content-hash">Content
          *     hash</a> page. Must have length of at least 64 and have length of
          *     at most 64.
diff --git a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartBuilder.java b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartBuilder.java
index 1b33da550..e117e2687 100644
--- a/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartBuilder.java
+++ b/core/build/generated_stone_source/main/src/com/dropbox/core/v2/files/UploadSessionStartBuilder.java
@@ -73,7 +73,8 @@ public UploadSessionStartBuilder withSessionType(UploadSessionType sessionType)
      *
      * @param contentHash  A hash of the file content uploaded in this call. If
      *     provided and the uploaded content does not match this hash, an error
-     *     will be returned. For more information see our <a
+     *     will be returned. Optional, but recommended to avoid committing data
+     *     corrupted in transit. For more information see our <a
      *     href="https://www.dropbox.com/developers/reference/content-hash">Content
      *     hash</a> page. Must have length of at least 64 and have length of at
      *     most 64.
diff --git a/core/src/main/stone b/core/src/main/stone
index 6d985dfaf..e733a5105 160000
--- a/core/src/main/stone
+++ b/core/src/main/stone
@@ -1 +1 @@
-Subproject commit 6d985dfaf901f1a909aa5e268bcfa524b0b7966e
+Subproject commit e733a5105a817d9a93e5c0f16f39d467d3e2072c