diff --git a/.hgtags b/.hgtags
index 3a18c29a8a60..dae4ea7adae7 100644
--- a/.hgtags
+++ b/.hgtags
@@ -127,3 +127,4 @@ fcef8ded82219c89298b4e376cfbdfba79a1d35a FIREFOX_AURORA_43_BASE
 68d3781deda0d4d58ec9877862830db89669b3a5 FIREFOX_AURORA_47_BASE
 1c6385ae1fe7e37d8f23f958ce14582f07af729e FIREFOX_AURORA_48_BASE
 d98f20c25feeac4dd7ebbd1c022957df1ef58af4 FIREFOX_AURORA_49_BASE
+465d150bc8be5bbf9f02a8607d4552b6a5e1697c FIREFOX_AURORA_50_BASE
diff --git a/CLOBBER b/CLOBBER
index 737040513edb..d4cdfaff33de 100644
--- a/CLOBBER
+++ b/CLOBBER
@@ -22,4 +22,4 @@
 # changes to stick? As of bug 928195, this shouldn't be necessary! Please
 # don't change CLOBBER for WebIDL changes any more.
 
-Bug 1287827 - Clobber needed because this patch removes files, second landing AND Bug 1272693 - Clobber required to rebuild NSS.
+Merge day clobber
\ No newline at end of file
diff --git a/browser/config/version.txt b/browser/config/version.txt
index fe73501df27f..20614dc3ade4 100644
--- a/browser/config/version.txt
+++ b/browser/config/version.txt
@@ -1 +1 @@
-50.0a1
+51.0a1
diff --git a/browser/config/version_display.txt b/browser/config/version_display.txt
index fe73501df27f..20614dc3ade4 100644
--- a/browser/config/version_display.txt
+++ b/browser/config/version_display.txt
@@ -1 +1 @@
-50.0a1
+51.0a1
diff --git a/config/milestone.txt b/config/milestone.txt
index 6ff45429aa01..9cf8f888011f 100644
--- a/config/milestone.txt
+++ b/config/milestone.txt
@@ -10,4 +10,4 @@
 # hardcoded milestones in the tree from these two files.
 #--------------------------------------------------------
 
-50.0a1
+51.0a1
diff --git a/services/sync/moz.build b/services/sync/moz.build
index 972a13816e17..ea60e0ddfd28 100644
--- a/services/sync/moz.build
+++ b/services/sync/moz.build
@@ -45,7 +45,7 @@ EXTRA_PP_JS_MODULES['services-sync'] += [
 ]
 
 # Definitions used by constants.js
-DEFINES['weave_version'] = '1.52.0'
+DEFINES['weave_version'] = '1.53.0'
 DEFINES['weave_id'] = '{340c2bbc-ce74-4362-90b5-7c26312808ef}'
 
 EXTRA_JS_MODULES['services-sync'].engines += [
diff --git a/xpcom/components/Module.h b/xpcom/components/Module.h
index a3fc6e8b8f63..4bcac8355a33 100644
--- a/xpcom/components/Module.h
+++ b/xpcom/components/Module.h
@@ -22,7 +22,7 @@ namespace mozilla {
  */
 struct Module
 {
-  static const unsigned int kVersion = 50;
+  static const unsigned int kVersion = 51;
 
   struct CIDEntry;