--- a/testing/mozharness/configs/multi_locale/mozilla-release_android-armv6.json
+++ b/testing/mozharness/configs/multi_locale/mozilla-release_android-armv6.json
@@ -15,15 +15,15 @@
         "branch": "production",
         "dest": "build/configs"
     },{
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",
         "dest": "tools"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "hg_l10n_tag": "default",
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build",
     "mozconfig": "build/mobile/android/config/mozconfigs/android-armv6/nightly"
 }

--- a/testing/mozharness/configs/multi_locale/mozilla-release_android-x86.json
+++ b/testing/mozharness/configs/multi_locale/mozilla-release_android-x86.json
@@ -15,15 +15,15 @@
         "branch": "production",
         "dest": "build/configs"
     },{
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",
         "dest": "tools"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "hg_l10n_tag": "default",
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build",
     "mozconfig": "build/mobile/android/config/mozconfigs/android-x86/nightly"
 }

--- a/testing/mozharness/configs/multi_locale/mozilla-release_android.json
+++ b/testing/mozharness/configs/multi_locale/mozilla-release_android.json
@@ -15,14 +15,14 @@
         "branch": "production",
         "dest": "build/configs"
     },{
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",
         "dest": "tools"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "hg_l10n_tag": "default",
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build"
 }

--- a/testing/mozharness/configs/multi_locale/release_mozilla-release_android-armv6.json
+++ b/testing/mozharness/configs/multi_locale/release_mozilla-release_android-armv6.json
@@ -20,15 +20,15 @@
         "dest": "tools"
     }],
     "l10n_repos": [{
         "repo": "https://hg.mozilla.org/build/buildbot-configs",
         "branch": "default",
         "dest": "build/configs"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "required_config_vars": ["tag_override"],
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build",
     "mozconfig": "build/mobile/android/config/mozconfigs/android-armv6/release"
 }

--- a/testing/mozharness/configs/multi_locale/release_mozilla-release_android-x86.json
+++ b/testing/mozharness/configs/multi_locale/release_mozilla-release_android-x86.json
@@ -20,15 +20,15 @@
         "dest": "tools"
     }],
     "l10n_repos": [{
         "repo": "https://hg.mozilla.org/build/buildbot-configs",
         "branch": "default",
         "dest": "build/configs"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "required_config_vars": ["tag_override"],
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build",
     "mozconfig": "build/mobile/android/config/mozconfigs/android-x86/release"
 }

--- a/testing/mozharness/configs/multi_locale/release_mozilla-release_android.json
+++ b/testing/mozharness/configs/multi_locale/release_mozilla-release_android.json
@@ -20,14 +20,14 @@
         "dest": "tools"
     }],
     "l10n_repos": [{
         "repo": "https://hg.mozilla.org/build/buildbot-configs",
         "branch": "default",
         "dest": "build/configs"
     }],
     "vcs_share_base": "/builds/hg-shared",
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "required_config_vars": ["tag_override"],
-    "l10n_dir": "mozilla-release",
+    "l10n_dir": "l10n-central",
     "merge_locales": true,
     "mozilla_dir": "build"
 }

--- a/testing/mozharness/configs/single_locale/dev-mozilla-release.py
+++ b/testing/mozharness/configs/single_locale/dev-mozilla-release.py
@@ -1,15 +1,15 @@
 config = {
     "branch": "jamun",
     "nightly_build": True,
     "update_channel": "release-dev",
 
     # l10n
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
 
     # repositories
     # staging release uses jamun
     "mozilla_dir": "jamun",
     "repos": [{
         "vcs": "hg",
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",

--- a/testing/mozharness/configs/single_locale/mozilla-esr52.py
+++ b/testing/mozharness/configs/single_locale/mozilla-esr52.py
@@ -1,8 +1,13 @@
+# This config references releases/l10n/mozilla-release instead of l10n-central
+# because 52 predates cross-channel localization, which rides the train
+# with 57.
+# If you copy this config for the ESR following 57, change hg_l10n_base
+# to l10n-central.
 config = {
     "nightly_build": True,
     "branch": "mozilla-esr52",
     "en_us_binary_url": "https://archive.mozilla.org/pub/mozilla.org/firefox/nightly/latest-mozilla-esr52/",
     "update_channel": "esr",
 
     # l10n
     "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",

--- a/testing/mozharness/configs/single_locale/mozilla-release.py
+++ b/testing/mozharness/configs/single_locale/mozilla-release.py
@@ -1,16 +1,16 @@
 config = {
     "nightly_build": True,
     "branch": "mozilla-release",
     "en_us_binary_url": "http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-mozilla-release/",
     "update_channel": "release",
 
     # l10n
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/mozilla-release",
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
 
     # repositories
     "mozilla_dir": "mozilla-release",
     "repos": [{
         "vcs": "hg",
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",
         "dest": "tools",

--- a/testing/mozharness/configs/single_locale/mozilla-release_android-api-16.py
+++ b/testing/mozharness/configs/single_locale/mozilla-release_android-api-16.py
@@ -36,20 +36,20 @@ config = {
         "repo": "https://hg.mozilla.org/releases/mozilla-release",
         "branch": "default",
         "dest": MOZILLA_DIR,
     }, {
         "repo": "https://hg.mozilla.org/build/tools",
         "branch": "default",
         "dest": "tools"
     }],
-    "hg_l10n_base": "https://hg.mozilla.org/releases/l10n/%s" % BRANCH,
+    "hg_l10n_base": "https://hg.mozilla.org/l10n-central",
     "hg_l10n_tag": "default",
     'vcs_share_base': HG_SHARE_BASE_DIR,
-    "l10n_dir": MOZILLA_DIR,
+    "l10n_dir": "l10n-central",
 
     "repack_env": {
         # so ugly, bug 951238
         "LD_LIBRARY_PATH": "/lib:/tools/gcc-4.7.2-0moz1/lib:/tools/gcc-4.7.2-0moz1/lib64",
         "EN_US_BINARY_URL": os.environ.get("EN_US_BINARY_URL", EN_US_BINARY_URL),
         "MOZ_OBJDIR": OBJDIR,
         "LOCALE_MERGEDIR": "%(abs_merge_dir)s/",
         "MOZ_UPDATE_CHANNEL": MOZ_UPDATE_CHANNEL,