--- a/testing/mozharness/configs/merge_day/aurora_to_beta.py
+++ b/testing/mozharness/configs/merge_day/aurora_to_beta.py
@@ -1,11 +1,17 @@
 config = {
     "log_name": "aurora_to_beta",
-
+    "version_files": [
+        "browser/config/version.txt",
+        "browser/config/version_display.txt",
+        "config/milestone.txt",
+        "mobile/android/confvars.sh",  # TODO: remove this line before gecko 43 merge
+        "b2g/confvars.sh",
+    ],
     "replacements": [
         # File, from, to
         ("{}/{}".format(d, f),
         "ac_add_options --with-branding=mobile/android/branding/aurora",
         "ac_add_options --with-branding=mobile/android/branding/beta")
         for d in ["mobile/android/config/mozconfigs/android-api-11/",
                   "mobile/android/config/mozconfigs/android-api-9-10-constrained/",
                   "mobile/android/config/mozconfigs/android-x86/"]

--- a/testing/mozharness/configs/merge_day/beta_to_release.py
+++ b/testing/mozharness/configs/merge_day/beta_to_release.py
@@ -1,10 +1,17 @@
 config = {
     "log_name": "beta_to_release",
+    "version_files": [
+        "browser/config/version.txt",
+        "browser/config/version_display.txt",
+        "config/milestone.txt",
+        "mobile/android/confvars.sh",  # TODO: remove this line before gecko 43 merge
+        "b2g/confvars.sh",
+    ],
     "replacements": [
         # File, from, to
         ("{}/{}".format(d, f),
         "ac_add_options --with-branding=mobile/android/branding/beta",
         "ac_add_options --with-branding=mobile/android/branding/official")
         for d in ["mobile/android/config/mozconfigs/android-api-11/",
                   "mobile/android/config/mozconfigs/android-api-9-10-constrained/",
                   "mobile/android/config/mozconfigs/android-x86/"]

--- a/testing/mozharness/configs/merge_day/central_to_aurora.py
+++ b/testing/mozharness/configs/merge_day/central_to_aurora.py
@@ -1,11 +1,16 @@
 config = {
     "log_name": "central_to_aurora",
-
+    "version_files": [
+        "browser/config/version.txt",
+        "browser/config/version_display.txt",
+        "config/milestone.txt",
+        "b2g/confvars.sh",
+    ],
     "replacements": [
         # File, from, to
         ("{}/{}".format(d, f),
         "ac_add_options --with-branding=mobile/android/branding/nightly",
         "ac_add_options --with-branding=mobile/android/branding/aurora")
         for d in ["mobile/android/config/mozconfigs/android-api-11/",
                   "mobile/android/config/mozconfigs/android-api-9-10-constrained/",
                   "mobile/android/config/mozconfigs/android-x86/"]

--- a/testing/mozharness/configs/merge_day/release_to_esr.py
+++ b/testing/mozharness/configs/merge_day/release_to_esr.py
@@ -1,14 +1,20 @@
 NEW_ESR_REPO = "ssh://hg.mozilla.org/releases/mozilla-esr45"
 OLD_ESR_REPO = "https://hg.mozilla.org/releases/mozilla-esr38"
 OLD_ESR_CHANGESET = "16351963d75c"
 
 config = {
     "log_name": "relese_to_esr",
+    "version_files": [
+        "browser/config/version.txt",
+        "browser/config/version_display.txt",
+        "config/milestone.txt",
+        "b2g/confvars.sh",
+    ],
     "replacements": [
         # File, from, to
         ("browser/confvars.sh",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-release",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-esr"),
         ("browser/confvars.sh",
          "MAR_CHANNEL_ID=firefox-mozilla-release",
          "MAR_CHANNEL_ID=firefox-mozilla-esr"),

--- a/testing/mozharness/scripts/merge_day/gecko_migration.py
+++ b/testing/mozharness/scripts/merge_day/gecko_migration.py
@@ -316,39 +316,31 @@ class GeckoMigration(MercurialScript, Ba
     def bump_version(self, cwd, curr_version, next_version, curr_suffix,
                      next_suffix, bump_major=False):
         """ Bump versions (m-c, m-a, m-b).
 
             At some point we may want to unhardcode these filenames into config
             """
         curr_weave_version = str(int(curr_version) + 2)
         next_weave_version = str(int(curr_weave_version) + 1)
-        version_files = ["browser/config/version.txt", "config/milestone.txt",
-                         "mobile/android/confvars.sh", "b2g/confvars.sh"]
-        # TODO: remove the following block when version_about.txt is all way to
-        # ESR (45?)
-        version_about = "browser/config/version_about.txt"
-        if os.path.exists(os.path.join(cwd, version_about)):
-            version_files.append(version_about)
-        # TODO: end of remove block
-        for f in version_files:
+        for f in self.config["version_files"]:
             self.replace(os.path.join(cwd, f), "%s.0%s" % (curr_version, curr_suffix),
                          "%s.0%s" % (next_version, next_suffix))
 
         # only applicable for m-c
         if bump_major:
             self.replace(
                 os.path.join(cwd, "xpcom/components/Module.h"),
                 "static const unsigned int kVersion = %s;" % curr_version,
                 "static const unsigned int kVersion = %s;" % next_version
             )
             self.replace(
-                os.path.join(cwd, "services/sync/Makefile.in"),
-                "weave_version := 1.%s.0" % curr_weave_version,
-                "weave_version := 1.%s.0" % next_weave_version
+                os.path.join(cwd, "services/sync/moz.build"),
+                "DEFINES['weave_version'] = '1.%s.0'" % curr_weave_version,
+                "DEFINES['weave_version'] = '1.%s.0'" % next_weave_version
             )
 
     # Branch-specific workflow helper methods {{{1
     def central_to_aurora(self, end_tag):
         """ mozilla-central -> mozilla-aurora behavior.
 
             We could have all of these individually toggled by flags, but
             by separating into workflow methods we can be more precise about