diff --git a/.travis.yml b/.travis.yml
index 3e2221d..16e325c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,8 +2,8 @@ language: bash
 services: docker
 
 env:
-  - VERSION=8.22
   - VERSION=9.0
+  - VERSION=9.1
 
 install:
   - git clone https://github.com/docker-library/official-images.git ~/official-images
diff --git a/8.22/Dockerfile b/9.1/Dockerfile
similarity index 66%
rename from 8.22/Dockerfile
rename to 9.1/Dockerfile
index 4acd9ad..decd650 100644
--- a/8.22/Dockerfile
+++ b/9.1/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:2.7.14-slim
+FROM python:2.7.16-slim-stretch
 
 # add our user and group first to make sure their IDs get assigned consistently
 RUN groupadd -r sentry && useradd -r -m -g sentry sentry
@@ -10,8 +10,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         libjpeg-dev \
         libpq-dev \
         libxml2-dev \
+        libxmlsec1-dev \
         libxslt-dev \
         libyaml-dev \
+        pkg-config \
     && rm -rf /var/lib/apt/lists/*
 
 # Sane defaults for pip
@@ -19,32 +21,56 @@ ENV PIP_NO_CACHE_DIR off
 ENV PIP_DISABLE_PIP_VERSION_CHECK on
 
 # grab gosu for easy step-down from root
-ENV GOSU_VERSION 1.10
 RUN set -x \
-    && apt-get update && apt-get install -y --no-install-recommends wget && rm -rf /var/lib/apt/lists/* \
+    && export GOSU_VERSION=1.11 \
+    && fetchDeps=" \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $fetchDeps && rm -rf /var/lib/apt/lists/* \
     && wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture)" \
     && wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture).asc" \
     && export GNUPGHOME="$(mktemp -d)" \
-    && gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4 \
+    && for key in \
+      B42F6819007F00F88E364FD4036A9C25BF357DD4 \
+    ; do \
+      gpg --batch --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://ipv4.pool.sks-keyservers.net --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
+    done \
     && gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu \
+    && gpgconf --kill all \
     && rm -r "$GNUPGHOME" /usr/local/bin/gosu.asc \
     && chmod +x /usr/local/bin/gosu \
     && gosu nobody true \
-    && apt-get purge -y --auto-remove wget
+    && apt-get purge -y --auto-remove $fetchDeps
 
 # grab tini for signal processing and zombie killing
-ENV TINI_VERSION v0.14.0
 RUN set -x \
-    && apt-get update && apt-get install -y --no-install-recommends wget && rm -rf /var/lib/apt/lists/* \
-    && wget -O /usr/local/bin/tini "https://github.com/krallin/tini/releases/download/$TINI_VERSION/tini" \
-    && wget -O /usr/local/bin/tini.asc "https://github.com/krallin/tini/releases/download/$TINI_VERSION/tini.asc" \
+    && export TINI_VERSION=0.18.0 \
+    && fetchDeps=" \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $fetchDeps && rm -rf /var/lib/apt/lists/* \
+    && wget -O /usr/local/bin/tini "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini" \
+    && wget -O /usr/local/bin/tini.asc "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini.asc" \
     && export GNUPGHOME="$(mktemp -d)" \
-    && gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys 6380DC428747F6C393FEACA59A84159D7001A4E5 \
+    && for key in \
+      595E85A6B1B4779EA4DAAEC70B588DFF0527A9B7 \
+    ; do \
+      gpg --batch --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://ipv4.pool.sks-keyservers.net --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
+    done \
     && gpg --batch --verify /usr/local/bin/tini.asc /usr/local/bin/tini \
+    && gpgconf --kill all \
     && rm -r "$GNUPGHOME" /usr/local/bin/tini.asc \
     && chmod +x /usr/local/bin/tini \
     && tini -h \
-    && apt-get purge -y --auto-remove wget
+&& apt-get purge -y --auto-remove $fetchDeps
 
 # Support for RabbitMQ
 RUN set -x \
@@ -53,26 +79,39 @@ RUN set -x \
     && python -c 'import librabbitmq' \
     && apt-get purge -y --auto-remove make
 
-ENV SENTRY_VERSION 8.22.0
+ENV SENTRY_VERSION 9.1.0
 
 RUN set -x \
-    && apt-get update && apt-get install -y --no-install-recommends wget g++ && rm -rf /var/lib/apt/lists/* \
+    && buildDeps=" \
+        g++ \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $buildDeps && rm -rf /var/lib/apt/lists/* \
     && mkdir -p /usr/src/sentry \
     && wget -O /usr/src/sentry/sentry-${SENTRY_VERSION}-py27-none-any.whl "https://github.com/getsentry/sentry/releases/download/${SENTRY_VERSION}/sentry-${SENTRY_VERSION}-py27-none-any.whl" \
     && wget -O /usr/src/sentry/sentry-${SENTRY_VERSION}-py27-none-any.whl.asc "https://github.com/getsentry/sentry/releases/download/${SENTRY_VERSION}/sentry-${SENTRY_VERSION}-py27-none-any.whl.asc" \
     && wget -O /usr/src/sentry/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl "https://github.com/getsentry/sentry/releases/download/${SENTRY_VERSION}/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl" \
     && wget -O /usr/src/sentry/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl.asc "https://github.com/getsentry/sentry/releases/download/${SENTRY_VERSION}/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl.asc" \
     && export GNUPGHOME="$(mktemp -d)" \
-    && gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys D8749766A66DD714236A932C3B2D400CE5BBCA60 \
+    && for key in \
+      D8749766A66DD714236A932C3B2D400CE5BBCA60 \
+    ; do \
+      gpg --batch --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://ipv4.pool.sks-keyservers.net --recv-keys "$key" || \
+      gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
+    done \
     && gpg --batch --verify /usr/src/sentry/sentry-${SENTRY_VERSION}-py27-none-any.whl.asc /usr/src/sentry/sentry-${SENTRY_VERSION}-py27-none-any.whl \
     && gpg --batch --verify /usr/src/sentry/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl.asc /usr/src/sentry/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl \
+    && gpgconf --kill all \
     && pip install \
         /usr/src/sentry/sentry-${SENTRY_VERSION}-py27-none-any.whl \
         /usr/src/sentry/sentry_plugins-${SENTRY_VERSION}-py2.py3-none-any.whl \
     && sentry --help \
     && sentry plugins list \
     && rm -r "$GNUPGHOME" /usr/src/sentry \
-    && apt-get purge -y --auto-remove wget g++
+    && apt-get purge -y --auto-remove $buildDeps
 
 ENV SENTRY_CONF=/etc/sentry \
     SENTRY_FILESTORE_DIR=/var/lib/sentry/files
diff --git a/8.22/config.yml b/9.1/config.yml
similarity index 100%
rename from 8.22/config.yml
rename to 9.1/config.yml
diff --git a/8.22/docker-entrypoint.sh b/9.1/docker-entrypoint.sh
similarity index 100%
rename from 8.22/docker-entrypoint.sh
rename to 9.1/docker-entrypoint.sh
diff --git a/8.22/onbuild/Dockerfile b/9.1/onbuild/Dockerfile
similarity index 97%
rename from 8.22/onbuild/Dockerfile
rename to 9.1/onbuild/Dockerfile
index 03a98ac..8979e00 100644
--- a/8.22/onbuild/Dockerfile
+++ b/9.1/onbuild/Dockerfile
@@ -1,4 +1,4 @@
-FROM sentry:8.22
+FROM sentry:9.1
 
 WORKDIR /usr/src/sentry
 
diff --git a/8.22/sentry.conf.py b/9.1/sentry.conf.py
similarity index 95%
rename from 8.22/sentry.conf.py
rename to 9.1/sentry.conf.py
index e4e0baf..5274992 100644
--- a/8.22/sentry.conf.py
+++ b/9.1/sentry.conf.py
@@ -29,6 +29,9 @@
 #  SENTRY_MAILGUN_API_KEY
 #  SENTRY_SINGLE_ORGANIZATION
 #  SENTRY_SECRET_KEY
+#  SLACK_CLIENT_ID
+#  SLACK_CLIENT_SECRET
+#  SLACK_VERIFICATION_TOKEN
 #  GITHUB_APP_ID
 #  GITHUB_API_SECRET
 #  BITBUCKET_CONSUMER_KEY
@@ -279,6 +282,15 @@
 if SENTRY_OPTIONS['mail.enable-replies']:
     SENTRY_OPTIONS['mail.reply-hostname'] = env('SENTRY_SMTP_HOSTNAME') or ''
 
+#####################
+# SLACK INTEGRATION #
+#####################
+slack = env('SLACK_CLIENT_ID') and env('SLACK_CLIENT_SECRET')
+if slack:
+    SENTRY_OPTIONS['slack.client-id'] = env('SLACK_CLIENT_ID')
+    SENTRY_OPTIONS['slack.client-secret'] = env('SLACK_CLIENT_SECRET')
+    SENTRY_OPTIONS['slack.verification-token'] = env('SLACK_VERIFICATION_TOKEN') or ''
+
 # If this value ever becomes compromised, it's important to regenerate your
 # SENTRY_SECRET_KEY. Changing this value will result in all current sessions
 # being invalidated.
diff --git a/generate-stackbrew-library.sh b/generate-stackbrew-library.sh
index 67273bb..4d27e95 100755
--- a/generate-stackbrew-library.sh
+++ b/generate-stackbrew-library.sh
@@ -3,8 +3,7 @@ set -eu
 
 declare -A aliases
 aliases=(
-	[8.22]='8'
-	[9.0]='9 latest'
+	[9.1]='9 latest'
 )
 
 self="$(basename "$BASH_SOURCE")"
diff --git a/git/Dockerfile b/git/Dockerfile
index fff9add..f2aa273 100644
--- a/git/Dockerfile
+++ b/git/Dockerfile
@@ -1,5 +1,5 @@
 # Build from any git sha by passing `--build-arg SENTRY_BUILD=<sha>`
-FROM python:2.7.15-slim-jessie
+FROM python:2.7.16-slim-stretch
 
 # add our user and group first to make sure their IDs get assigned consistently
 RUN groupadd -r sentry && useradd -r -m -g sentry sentry
@@ -25,7 +25,12 @@ ENV PIP_DISABLE_PIP_VERSION_CHECK on
 # grab gosu for easy step-down from root
 RUN set -x \
     && export GOSU_VERSION=1.11 \
-    && apt-get update && apt-get install -y --no-install-recommends wget && rm -rf /var/lib/apt/lists/* \
+    && fetchDeps=" \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $fetchDeps && rm -rf /var/lib/apt/lists/* \
     && wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture)" \
     && wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture).asc" \
     && export GNUPGHOME="$(mktemp -d)" \
@@ -37,15 +42,21 @@ RUN set -x \
       gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
     done \
     && gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu \
+    && gpgconf --kill all \
     && rm -r "$GNUPGHOME" /usr/local/bin/gosu.asc \
     && chmod +x /usr/local/bin/gosu \
     && gosu nobody true \
-    && apt-get purge -y --auto-remove wget
+    && apt-get purge -y --auto-remove $fetchDeps
 
 # grab tini for signal processing and zombie killing
 RUN set -x \
     && export TINI_VERSION=0.18.0 \
-    && apt-get update && apt-get install -y --no-install-recommends wget && rm -rf /var/lib/apt/lists/* \
+    && fetchDeps=" \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $fetchDeps && rm -rf /var/lib/apt/lists/* \
     && wget -O /usr/local/bin/tini "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini" \
     && wget -O /usr/local/bin/tini.asc "https://github.com/krallin/tini/releases/download/v$TINI_VERSION/tini.asc" \
     && export GNUPGHOME="$(mktemp -d)" \
@@ -57,10 +68,11 @@ RUN set -x \
       gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
     done \
     && gpg --batch --verify /usr/local/bin/tini.asc /usr/local/bin/tini \
+    && gpgconf --kill all \
     && rm -r "$GNUPGHOME" /usr/local/bin/tini.asc \
     && chmod +x /usr/local/bin/tini \
     && tini -h \
-    && apt-get purge -y --auto-remove wget
+&& apt-get purge -y --auto-remove $fetchDeps
 
 # Support for RabbitMQ
 RUN set -x \
@@ -74,11 +86,19 @@ ENV SENTRY_BUILD $SENTRY_BUILD
 
 RUN [ "$SENTRY_BUILD" != '' ] \
     # Install node to build assets
-    && export NODE_VERSION=8.10.0 \
+    && export NODE_VERSION=8.15.1 \
     && export YARN_VERSION=1.13.0 \
     && export GNUPGHOME="$(mktemp -d)" \
     && export NPM_CONFIG_CACHE="$(mktemp -d)" \
     && export YARN_CACHE_FOLDER="$(mktemp -d)" \
+    && buildDeps=" \
+        make \
+        g++ \
+        dirmngr \
+        gnupg \
+        wget \
+    " \
+    && apt-get update && apt-get install -y --no-install-recommends $buildDeps && rm -rf /var/lib/apt/lists/* \
     # gpg keys listed at https://github.com/nodejs/node
     && set -ex \
     && for key in \
@@ -99,11 +119,11 @@ RUN [ "$SENTRY_BUILD" != '' ] \
       gpg --batch --keyserver hkp://pgp.mit.edu:80 --recv-keys "$key" ; \
     done \
     && mkdir -p /usr/local/node && PATH=/usr/local/node/bin:$PATH \
-    && apt-get update && apt-get install -y --no-install-recommends make g++ wget \
     && rm -rf /var/lib/apt/lists/* \
     && wget "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64.tar.gz" \
     && wget "https://nodejs.org/dist/v$NODE_VERSION/SHASUMS256.txt.asc" \
     && gpg --batch --verify SHASUMS256.txt.asc \
+    && gpgconf --kill all \
     && grep " node-v$NODE_VERSION-linux-x64.tar.gz\$" SHASUMS256.txt.asc | sha256sum -c - \
     && tar -xzf "node-v$NODE_VERSION-linux-x64.tar.gz" -C /usr/local/node --strip-components=1 \
     && rm -r "$GNUPGHOME" "node-v$NODE_VERSION-linux-x64.tar.gz" SHASUMS256.txt.asc \
@@ -120,7 +140,7 @@ RUN [ "$SENTRY_BUILD" != '' ] \
 
     && pip install dist/*.whl \
 
-    && apt-get purge -y --auto-remove make g++ wget \
+    && apt-get purge -y --auto-remove $buildDeps \
     && rm -rf /usr/src/sentry
 
 ENV SENTRY_CONF=/etc/sentry \
diff --git a/update.sh b/update.sh
index 9eefe21..ccafec4 100755
--- a/update.sh
+++ b/update.sh
@@ -4,4 +4,4 @@ set -e
 current="$(curl -sSL 'https://pypi.python.org/pypi/sentry/json' | awk -F '"' '$2 == "version" { print $4 }')"
 
 set -x
-sed -ri 's/^(ENV SENTRY_VERSION) .*/\1 '"$current"'/' 9.0/Dockerfile
+sed -ri 's/^(ENV SENTRY_VERSION) .*/\1 '"$current"'/' 9.1/Dockerfile