diff --git a/README.md b/README.md
index a55d214..29154ae 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Docker hub: [https://registry.hub.docker.com/u/jumanjiman/duoauthproxy/](https:/
 <br />
 Image metadata: [https://microbadger.com/#/images/jumanjiman/duoauthproxy](https://microbadger.com/#/images/jumanjiman/duoauthproxy)
 <br />
-Current version: Duo Authproxy 2.7.0
+Current version: Duo Authproxy 2.9.0
 ([release notes](https://duo.com/support/documentation/authproxy-notes))
 
 :warning: Duo Authproxy 2.4.18 resolves
diff --git a/builder/Dockerfile b/builder/Dockerfile
index b808e75..ec99ec4 100644
--- a/builder/Dockerfile
+++ b/builder/Dockerfile
@@ -11,11 +11,13 @@ RUN apk upgrade --update --available && \
       libffi-dev \
       libgcc \
       'libressl-dev>=2.6.3-r0' \
+      linux-headers \
       make \
       patch \
       py-setuptools \
       python-dev \
       tar \
+      zlib-dev \
     && rm -f /var/cache/apk/* && \
     adduser -D duo
 
diff --git a/ci/build.sh b/ci/build.sh
index 7f7efdc..dd48581 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -12,7 +12,7 @@ set -o pipefail
 
 cat >ci/vars <<EOF
 # shellcheck shell=bash
-declare -rx  VERSION=2.7.0
+declare -rx  VERSION=2.9.0
 declare -rx  BUILD_DATE=$(date +%Y%m%dT%H%M)
 declare -rx  VCS_REF=$(git describe --abbrev=7 --tags --always)
 declare -rx  TAG=\${VERSION}-\${BUILD_DATE}-git-\${VCS_REF}