--- a/maxversions.mk
+++ b/maxversions.mk
@@ -1,24 +1,11 @@
-#
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-
-SEAMONKEY_VERSION := $(shell cat $(topsrcdir)/../suite/config/version.txt)
-FIREFOX_VERSION := $(shell cat $(topsrcdir)/browser/config/version.txt)
-
 # For extensions we require a max version that is compatible across security releases.
 # FIREFOX_MAXVERSION and SEAMONKEY_MAXVERSION is our method for doing that.
 # Alpha versions 10.0a1 and 10.0a2 aren't affected
 # For Seamonkey, 2.17 becomes 2.17.*, 2.17.1 becomes 2.17.*
 # For Firefox, 10.0 becomes 10.*, 10.0.1 becomes 10.*
-SEAMONKEY_MAXVERSION := $(SEAMONKEY_VERSION)
-ifneq (a,$(findstring a,$(SEAMONKEY_VERSION)))
-SEAMONKEY_MAXVERSION := $(shell echo $(SEAMONKEY_VERSION) | sed 's|\(^[0-9]*.[0-9]*\).*|\1|' ).*
-endif
-
-FIREFOX_MAXVERSION := $(FIREFOX_VERSION)
-ifneq (a,$(findstring a,$(FIREFOX_VERSION)))
-FIREFOX_MAXVERSION := $(shell echo $(FIREFOX_VERSION) | sed 's|\(^[0-9]*\)\.\([0-9]*\).*|\1|' ).*
-endif
-
+SEAMONKEY_MAXVERSION := 2.57.*
+FIREFOX_MAXVERSION := 56.*

--- a/xpi/makexpi.py
+++ b/xpi/makexpi.py
@@ -17,18 +17,18 @@ import sys
 import shutil
 import re
 import zipfile
 from os.path import join as joinpath
 
 # Set up settings and paths for finding files.
 pwd = os.path.dirname(__file__)
 
-ffversion = '45.*'
-smversion = '2.42.*'
+ffversion = '56.*'
+smversion = '2.57.*'
 
 if pwd == '':
     pwd = os.getcwd()
 else:
     os.chdir(pwd)
 
 def getenv(var, default, dir=False, check=False):
     """