diff --git a/.travis.yml b/.travis.yml
index 6434beb..9ba3e70 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,12 +3,8 @@ language: bash
 services: docker
 
 env:
+  - VERSION=2.8 LATEST=true
   - VERSION=2.5
-  - VERSION=2.4 LATEST=true
-  - VERSION=2.3
-  - VERSION=2.2
-  - VERSION=2.0
-  - VERSION=1.9
 
 before_install:
   - sudo add-apt-repository ppa:duggan/bats --yes
@@ -16,7 +12,6 @@ before_install:
   - sudo apt-get install -qq bats
 
 before_script:
-  - env | sort
   - export IMAGE="mini/ansible:${VERSION}"
 
 script:
@@ -24,7 +19,8 @@ script:
     (
       set -Eeuo pipefail
       set -x
-      travis_retry docker build -t "$IMAGE" $VERSION/
+      docker pull "$IMAGE" || true
+      travis_retry docker build --cache-from "$IMAGE" -t "$IMAGE" $VERSION/
       IMAGE=$IMAGE VERSION=$VERSION bats tests/
     )
 
diff --git a/1.9/Dockerfile b/1.9/Dockerfile
deleted file mode 100644
index 5b8e86c..0000000
--- a/1.9/Dockerfile
+++ /dev/null
@@ -1,38 +0,0 @@
-# Latest Python 2.x using latest Alpine 3.7
-FROM python:2-alpine
-
-# default playbook directory
-WORKDIR /data
-
-ENV ANSIBLE_VERSION 1.9.6
-
-# install general runtime dependencies
-RUN set -ex \
-        && apk add --no-cache \
-                openssh-client \
-                openssl
-
-# 1. install build dependencies, then pip ansible.
-# 2. detect any compiled extension that requires runtime dependencies.
-# (copied from official Docker's Python image)
-RUN set -ex \
-        && apk add --no-cache --virtual .build-deps \
-                gcc \
-                libffi-dev \
-                openssl-dev \
-                linux-headers \
-                make \
-                musl-dev \
-        && pip install --upgrade --no-cache-dir \
-                ansible==$ANSIBLE_VERSION \
-                passlib \
-        && runDeps="$( \
-                scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
-                        | tr ',' '\n' \
-                        | sort -u \
-                        | awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
-        )" \
-        && apk add --virtual .ansible-rundeps $runDeps \
-        && apk del .build-deps
-
-CMD ["ansible-playbook", "--version"]
diff --git a/2.0/Dockerfile b/2.0/Dockerfile
deleted file mode 100644
index 0be88e2..0000000
--- a/2.0/Dockerfile
+++ /dev/null
@@ -1,38 +0,0 @@
-# Latest Python 2.x using Alpine
-FROM python:2-alpine
-
-# default playbook directory
-WORKDIR /data
-
-ENV ANSIBLE_VERSION 2.0.2
-
-# install general runtime dependencies
-RUN set -ex \
-        && apk add --no-cache \
-                openssh-client \
-                openssl
-
-# 1. install build dependencies, then pip ansible.
-# 2. detect any compiled extension that requires runtime dependencies.
-# (copied from official Docker's Python image)
-RUN set -ex \
-        && apk add --no-cache --virtual .build-deps \
-                gcc \
-                libffi-dev \
-                openssl-dev \
-                linux-headers \
-                make \
-                musl-dev \
-        && pip install --upgrade --no-cache-dir \
-                ansible==$ANSIBLE_VERSION \
-                passlib \
-        && runDeps="$( \
-                scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
-                        | tr ',' '\n' \
-                        | sort -u \
-                        | awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
-        )" \
-        && apk add --virtual .ansible-rundeps $runDeps \
-        && apk del .build-deps
-
-CMD ["ansible-playbook", "--version"]
diff --git a/2.2/Dockerfile b/2.2/Dockerfile
deleted file mode 100644
index 21dfe15..0000000
--- a/2.2/Dockerfile
+++ /dev/null
@@ -1,38 +0,0 @@
-# Latest Python 2.x using latest Alpine 3.7
-FROM python:2-alpine3.7
-
-# default playbook directory
-WORKDIR /data
-
-ENV ANSIBLE_VERSION 2.2.1
-
-# install general runtime dependencies
-RUN set -ex \
-        && apk add --no-cache \
-                openssh-client \
-                openssl
-
-# 1. install build dependencies, then pip ansible.
-# 2. detect any compiled extension that requires runtime dependencies.
-# (copied from official Docker's Python image)
-RUN set -ex \
-        && apk add --no-cache --virtual .build-deps \
-                gcc \
-                libffi-dev \
-                libressl-dev \
-                linux-headers \
-                make \
-                musl-dev \
-        && pip install --upgrade --no-cache-dir \
-                ansible==$ANSIBLE_VERSION \
-                passlib \
-        && runDeps="$( \
-                scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
-                        | tr ',' '\n' \
-                        | sort -u \
-                        | awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
-        )" \
-        && apk add --virtual .ansible-rundeps $runDeps \
-        && apk del .build-deps
-
-CMD ["ansible-playbook", "--version"]
diff --git a/2.3/Dockerfile b/2.3/Dockerfile
deleted file mode 100644
index 4bf457a..0000000
--- a/2.3/Dockerfile
+++ /dev/null
@@ -1,38 +0,0 @@
-# Latest Python 2.x using latest Alpine 3.7
-FROM python:2-alpine3.7
-
-# default playbook directory
-WORKDIR /data
-
-ENV ANSIBLE_VERSION 2.3.3
-
-# install general runtime dependencies
-RUN set -ex \
-        && apk add --no-cache \
-                openssh-client \
-                openssl
-
-# 1. install build dependencies, then pip ansible.
-# 2. detect any compiled extension that requires runtime dependencies.
-# (copied from official Docker's Python image)
-RUN set -ex \
-        && apk add --no-cache --virtual .build-deps \
-                gcc \
-                libffi-dev \
-                libressl-dev \
-                linux-headers \
-                make \
-                musl-dev \
-        && pip install --upgrade --no-cache-dir \
-                ansible==$ANSIBLE_VERSION \
-                passlib \
-        && runDeps="$( \
-                scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
-                        | tr ',' '\n' \
-                        | sort -u \
-                        | awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
-        )" \
-        && apk add --virtual .ansible-rundeps $runDeps \
-        && apk del .build-deps
-
-CMD ["ansible-playbook", "--version"]
diff --git a/2.5/Dockerfile b/2.5/Dockerfile
index 4c6dedf..75d532b 100644
--- a/2.5/Dockerfile
+++ b/2.5/Dockerfile
@@ -1,10 +1,10 @@
 # Latest Python 2.x using latest Alpine 3.7
-FROM python:2-alpine3.7
+FROM python:2-alpine3.9
 
 # default playbook directory
 WORKDIR /data
 
-ENV ANSIBLE_VERSION 2.5.0
+ENV ANSIBLE_VERSION 2.5.15
 
 # install general runtime dependencies
 RUN set -ex \
diff --git a/2.4/Dockerfile b/2.8/Dockerfile
similarity index 92%
rename from 2.4/Dockerfile
rename to 2.8/Dockerfile
index a7877a8..e0eaa37 100644
--- a/2.4/Dockerfile
+++ b/2.8/Dockerfile
@@ -1,10 +1,10 @@
-# Latest Python 2.x using latest Alpine 3.7
-FROM python:2-alpine3.7
+# Latest Python 2.x using latest Alpine 3.9
+FROM python:2-alpine3.9
 
 # default playbook directory
 WORKDIR /data
 
-ENV ANSIBLE_VERSION 2.4.4
+ENV ANSIBLE_VERSION 2.8.1
 
 # install general runtime dependencies
 RUN set -ex \