diff --git a/cni.Dockerfile b/cni.Dockerfile
index 33c97d953..e25115be5 100644
--- a/cni.Dockerfile
+++ b/cni.Dockerfile
@@ -7,7 +7,7 @@ RUN go build -o /go/bin/kuryr-cni ./kuryr_cni
 FROM centos:7
 LABEL authors="Antoni Segura Puimedon<toni@kuryr.org>, Michał Dulko<mdulko@redhat.com>"
 
-ARG UPPER_CONSTRAINTS_FILE="https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt"
+ARG UPPER_CONSTRAINTS_FILE="https://releases.openstack.org/constraints/upper/train"
 ARG OSLO_LOCK_PATH=/var/kuryr-lock
 
 RUN yum install -y epel-release https://rdoproject.org/repos/rdo-release.rpm \
diff --git a/cni_py3.Dockerfile b/cni_py3.Dockerfile
index 995a58c18..31c2e75a3 100644
--- a/cni_py3.Dockerfile
+++ b/cni_py3.Dockerfile
@@ -7,7 +7,7 @@ RUN go build -o /go/bin/kuryr-cni ./kuryr_cni
 FROM fedora:30
 LABEL authors="Antoni Segura Puimedon<toni@kuryr.org>, Michał Dulko<mdulko@redhat.com>"
 
-ARG UPPER_CONSTRAINTS_FILE="https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt"
+ARG UPPER_CONSTRAINTS_FILE="https://releases.openstack.org/constraints/upper/train"
 ARG OSLO_LOCK_PATH=/var/kuryr-lock
 
 RUN dnf update -y \
diff --git a/controller.Dockerfile b/controller.Dockerfile
index ebfcc7fe9..40f8599d8 100644
--- a/controller.Dockerfile
+++ b/controller.Dockerfile
@@ -1,7 +1,7 @@
 FROM centos:7
 LABEL authors="Antoni Segura Puimedon<toni@kuryr.org>, Michał Dulko<mdulko@redhat.com>"
 
-ARG UPPER_CONSTRAINTS_FILE="https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt"
+ARG UPPER_CONSTRAINTS_FILE="https://releases.openstack.org/constraints/upper/train"
 
 RUN yum install -y epel-release \
     && yum install -y --setopt=tsflags=nodocs python-pip libstdc++ \
diff --git a/controller_py3.Dockerfile b/controller_py3.Dockerfile
index 9f633175a..385208671 100644
--- a/controller_py3.Dockerfile
+++ b/controller_py3.Dockerfile
@@ -1,7 +1,7 @@
 FROM fedora:30
 LABEL authors="Antoni Segura Puimedon<toni@kuryr.org>, Michał Dulko<mdulko@redhat.com>"
 
-ARG UPPER_CONSTRAINTS_FILE="https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt"
+ARG UPPER_CONSTRAINTS_FILE="https://releases.openstack.org/constraints/upper/train"
 
 RUN dnf update -y \
     && dnf install -y --setopt=tsflags=nodocs python36 libstdc++ \
diff --git a/devstack/lib/kuryr_kubernetes b/devstack/lib/kuryr_kubernetes
index 4a83428f1..cdcddc945 100644
--- a/devstack/lib/kuryr_kubernetes
+++ b/devstack/lib/kuryr_kubernetes
@@ -163,11 +163,11 @@ function _allocation_range {
   python - <<EOF "$@"
 import sys
 
-from ipaddress import ip_network
+from netaddr import IPNetwork
 import six
 
 
-n = ip_network(six.text_type(sys.argv[1]))
+n = IPNetwork(six.text_type(sys.argv[1]))
 gateway_position = sys.argv[2]
 
 if gateway_position == 'beginning':
@@ -1013,12 +1013,12 @@ function split_subnet {
     python - <<EOF "$@"
 import sys
 
-from ipaddress import ip_network
+from netaddr import IPNetwork
 import six
 
 
-n = ip_network(six.text_type(sys.argv[1]))
-first, last = n.subnets(prefixlen_diff=1)
+n = IPNetwork(six.text_type(sys.argv[1]))
+first, last = n.subnet(n.prefixlen+1)
 
 print("%s\\t%s" % (first, last))
 EOF