diff --git a/certbot-postfix/local-oldest-requirements.txt b/certbot-postfix/local-oldest-requirements.txt
index cbcfc4d0c..bc0cdbf00 100644
--- a/certbot-postfix/local-oldest-requirements.txt
+++ b/certbot-postfix/local-oldest-requirements.txt
@@ -1,2 +1,2 @@
--e acme[dev]
+acme[dev]==0.25.0
 certbot[dev]==0.23.0
diff --git a/certbot-postfix/setup.py b/certbot-postfix/setup.py
index 83eed06d1..cde1ac7c2 100644
--- a/certbot-postfix/setup.py
+++ b/certbot-postfix/setup.py
@@ -2,7 +2,7 @@ from setuptools import setup
 from setuptools import find_packages
 
 
-version = '0.24.0.dev0'
+version = '0.26.0.dev0'
 
 install_requires = [
     'acme>=0.25.0',