diff --git a/.travis.yml b/.travis.yml
index 30d9b7fc2..cbd03ade3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,12 +18,6 @@ env:
   - VERSION=2.5 VARIANT=stretch/slim
   - VERSION=2.5 VARIANT=alpine3.11
   - VERSION=2.5 VARIANT=alpine3.10
-  - VERSION=2.4 VARIANT=buster
-  - VERSION=2.4 VARIANT=buster/slim
-  - VERSION=2.4 VARIANT=stretch
-  - VERSION=2.4 VARIANT=stretch/slim
-  - VERSION=2.4 VARIANT=alpine3.11
-  - VERSION=2.4 VARIANT=alpine3.10
 
 install:
   - git clone --depth 1 https://github.com/docker-library/official-images.git ~/official-images
diff --git a/2.4/alpine3.10/Dockerfile b/2.4/alpine3.10/Dockerfile
deleted file mode 100644
index 0529f0daf..000000000
--- a/2.4/alpine3.10/Dockerfile
+++ /dev/null
@@ -1,132 +0,0 @@
-FROM alpine:3.10
-
-RUN apk add --no-cache \
-		gmp-dev
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-# readline-dev vs libedit-dev: https://bugs.ruby-lang.org/issues/11869 and https://github.com/docker-library/ruby/issues/75
-RUN set -eux; \
-	\
-	apk add --no-cache --virtual .ruby-builddeps \
-		autoconf \
-		bison \
-		bzip2 \
-		bzip2-dev \
-		ca-certificates \
-		coreutils \
-		dpkg-dev dpkg \
-		gcc \
-		gdbm-dev \
-		glib-dev \
-		libc-dev \
-		libffi-dev \
-		libxml2-dev \
-		libxslt-dev \
-		linux-headers \
-		make \
-		ncurses-dev \
-		openssl \
-		openssl-dev \
-		procps \
-		readline-dev \
-		ruby \
-		tar \
-		xz \
-		yaml-dev \
-		zlib-dev \
-	; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# https://github.com/docker-library/ruby/issues/196
-# https://bugs.ruby-lang.org/issues/14387#note-13 (patch source)
-# https://bugs.ruby-lang.org/issues/14387#note-16 ("Therefore ncopa's patch looks good for me in general." -- only breaks glibc which doesn't matter here)
-	wget -O 'thread-stack-fix.patch' 'https://bugs.ruby-lang.org/attachments/download/7081/0001-thread_pthread.c-make-get_main_stack-portable-on-lin.patch'; \
-	echo '3ab628a51d92fdf0d2b5835e93564857aea73e0c1de00313864a94a6255cb645 *thread-stack-fix.patch' | sha256sum --check --strict; \
-	patch -p1 -i thread-stack-fix.patch; \
-	rm thread-stack-fix.patch; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-# the configure script does not detect isnan/isinf as macros
-	export ac_cv_func_isnan=yes ac_cv_func_isinf=yes; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	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 --no-network --virtual .ruby-rundeps \
-		$runDeps \
-		bzip2 \
-		ca-certificates \
-		libffi-dev \
-		procps \
-		yaml-dev \
-		zlib-dev \
-	; \
-	apk del --no-network .ruby-builddeps; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! apk --no-network list --installed \
-		| grep -v '^[.]ruby-rundeps' \
-		| grep -i ruby \
-	; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]
diff --git a/2.4/alpine3.11/Dockerfile b/2.4/alpine3.11/Dockerfile
deleted file mode 100644
index 25b4cc6fe..000000000
--- a/2.4/alpine3.11/Dockerfile
+++ /dev/null
@@ -1,132 +0,0 @@
-FROM alpine:3.11
-
-RUN apk add --no-cache \
-		gmp-dev
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-# readline-dev vs libedit-dev: https://bugs.ruby-lang.org/issues/11869 and https://github.com/docker-library/ruby/issues/75
-RUN set -eux; \
-	\
-	apk add --no-cache --virtual .ruby-builddeps \
-		autoconf \
-		bison \
-		bzip2 \
-		bzip2-dev \
-		ca-certificates \
-		coreutils \
-		dpkg-dev dpkg \
-		gcc \
-		gdbm-dev \
-		glib-dev \
-		libc-dev \
-		libffi-dev \
-		libxml2-dev \
-		libxslt-dev \
-		linux-headers \
-		make \
-		ncurses-dev \
-		openssl \
-		openssl-dev \
-		procps \
-		readline-dev \
-		ruby \
-		tar \
-		xz \
-		yaml-dev \
-		zlib-dev \
-	; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# https://github.com/docker-library/ruby/issues/196
-# https://bugs.ruby-lang.org/issues/14387#note-13 (patch source)
-# https://bugs.ruby-lang.org/issues/14387#note-16 ("Therefore ncopa's patch looks good for me in general." -- only breaks glibc which doesn't matter here)
-	wget -O 'thread-stack-fix.patch' 'https://bugs.ruby-lang.org/attachments/download/7081/0001-thread_pthread.c-make-get_main_stack-portable-on-lin.patch'; \
-	echo '3ab628a51d92fdf0d2b5835e93564857aea73e0c1de00313864a94a6255cb645 *thread-stack-fix.patch' | sha256sum --check --strict; \
-	patch -p1 -i thread-stack-fix.patch; \
-	rm thread-stack-fix.patch; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-# the configure script does not detect isnan/isinf as macros
-	export ac_cv_func_isnan=yes ac_cv_func_isinf=yes; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	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 --no-network --virtual .ruby-rundeps \
-		$runDeps \
-		bzip2 \
-		ca-certificates \
-		libffi-dev \
-		procps \
-		yaml-dev \
-		zlib-dev \
-	; \
-	apk del --no-network .ruby-builddeps; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! apk --no-network list --installed \
-		| grep -v '^[.]ruby-rundeps' \
-		| grep -i ruby \
-	; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]
diff --git a/2.4/buster/Dockerfile b/2.4/buster/Dockerfile
deleted file mode 100644
index 8b79d2928..000000000
--- a/2.4/buster/Dockerfile
+++ /dev/null
@@ -1,91 +0,0 @@
-FROM buildpack-deps:buster
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-RUN set -eux; \
-	\
-	savedAptMark="$(apt-mark showmanual)"; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		bison \
-		dpkg-dev \
-		libgdbm-dev \
-		ruby \
-	; \
-	rm -rf /var/lib/apt/lists/*; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	apt-mark auto '.*' > /dev/null; \
-	apt-mark manual $savedAptMark > /dev/null; \
-	find /usr/local -type f -executable -not \( -name '*tkinter*' \) -exec ldd '{}' ';' \
-		| awk '/=>/ { print $(NF-1) }' \
-		| sort -u \
-		| xargs -r dpkg-query --search \
-		| cut -d: -f1 \
-		| sort -u \
-		| xargs -r apt-mark manual \
-	; \
-	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! dpkg -l | grep -i ruby; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]
diff --git a/2.4/buster/slim/Dockerfile b/2.4/buster/slim/Dockerfile
deleted file mode 100644
index 7346987f8..000000000
--- a/2.4/buster/slim/Dockerfile
+++ /dev/null
@@ -1,117 +0,0 @@
-FROM debian:buster-slim
-
-RUN set -eux; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		bzip2 \
-		ca-certificates \
-		libffi-dev \
-		libgmp-dev \
-		libssl-dev \
-		libyaml-dev \
-		procps \
-		zlib1g-dev \
-	; \
-	rm -rf /var/lib/apt/lists/*
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-RUN set -eux; \
-	\
-	savedAptMark="$(apt-mark showmanual)"; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		autoconf \
-		bison \
-		dpkg-dev \
-		gcc \
-		libbz2-dev \
-		libgdbm-compat-dev \
-		libgdbm-dev \
-		libglib2.0-dev \
-		libncurses-dev \
-		libreadline-dev \
-		libxml2-dev \
-		libxslt-dev \
-		make \
-		ruby \
-		wget \
-		xz-utils \
-	; \
-	rm -rf /var/lib/apt/lists/*; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	apt-mark auto '.*' > /dev/null; \
-	apt-mark manual $savedAptMark > /dev/null; \
-	find /usr/local -type f -executable -not \( -name '*tkinter*' \) -exec ldd '{}' ';' \
-		| awk '/=>/ { print $(NF-1) }' \
-		| sort -u \
-		| xargs -r dpkg-query --search \
-		| cut -d: -f1 \
-		| sort -u \
-		| xargs -r apt-mark manual \
-	; \
-	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! dpkg -l | grep -i ruby; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]
diff --git a/2.4/stretch/Dockerfile b/2.4/stretch/Dockerfile
deleted file mode 100644
index e45b9c24d..000000000
--- a/2.4/stretch/Dockerfile
+++ /dev/null
@@ -1,91 +0,0 @@
-FROM buildpack-deps:stretch
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-RUN set -eux; \
-	\
-	savedAptMark="$(apt-mark showmanual)"; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		bison \
-		dpkg-dev \
-		libgdbm-dev \
-		ruby \
-	; \
-	rm -rf /var/lib/apt/lists/*; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	apt-mark auto '.*' > /dev/null; \
-	apt-mark manual $savedAptMark > /dev/null; \
-	find /usr/local -type f -executable -not \( -name '*tkinter*' \) -exec ldd '{}' ';' \
-		| awk '/=>/ { print $(NF-1) }' \
-		| sort -u \
-		| xargs -r dpkg-query --search \
-		| cut -d: -f1 \
-		| sort -u \
-		| xargs -r apt-mark manual \
-	; \
-	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! dpkg -l | grep -i ruby; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]
diff --git a/2.4/stretch/slim/Dockerfile b/2.4/stretch/slim/Dockerfile
deleted file mode 100644
index 8a078383e..000000000
--- a/2.4/stretch/slim/Dockerfile
+++ /dev/null
@@ -1,116 +0,0 @@
-FROM debian:stretch-slim
-
-RUN set -eux; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		bzip2 \
-		ca-certificates \
-		libffi-dev \
-		libgmp-dev \
-		libssl-dev \
-		libyaml-dev \
-		procps \
-		zlib1g-dev \
-	; \
-	rm -rf /var/lib/apt/lists/*
-
-# skip installing gem documentation
-RUN set -eux; \
-	mkdir -p /usr/local/etc; \
-	{ \
-		echo 'install: --no-document'; \
-		echo 'update: --no-document'; \
-	} >> /usr/local/etc/gemrc
-
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.10
-ENV RUBY_DOWNLOAD_SHA256 d5668ed11544db034f70aec37d11e157538d639ed0d0a968e2f587191fc530df
-ENV RUBYGEMS_VERSION 3.0.3
-
-# some of ruby's build scripts are written in ruby
-#   we purge system ruby later to make sure our final image uses what we just built
-RUN set -eux; \
-	\
-	savedAptMark="$(apt-mark showmanual)"; \
-	apt-get update; \
-	apt-get install -y --no-install-recommends \
-		autoconf \
-		bison \
-		dpkg-dev \
-		gcc \
-		libbz2-dev \
-		libgdbm-dev \
-		libglib2.0-dev \
-		libncurses-dev \
-		libreadline-dev \
-		libxml2-dev \
-		libxslt-dev \
-		make \
-		ruby \
-		wget \
-		xz-utils \
-	; \
-	rm -rf /var/lib/apt/lists/*; \
-	\
-	wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz"; \
-	echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum --check --strict; \
-	\
-	mkdir -p /usr/src/ruby; \
-	tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1; \
-	rm ruby.tar.xz; \
-	\
-	cd /usr/src/ruby; \
-	\
-# hack in "ENABLE_PATH_CHECK" disabling to suppress:
-#   warning: Insecure world writable dir
-	{ \
-		echo '#define ENABLE_PATH_CHECK 0'; \
-		echo; \
-		cat file.c; \
-	} > file.c.new; \
-	mv file.c.new file.c; \
-	\
-	autoconf; \
-	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
-	./configure \
-		--build="$gnuArch" \
-		--disable-install-doc \
-		--enable-shared \
-	; \
-	make -j "$(nproc)"; \
-	make install; \
-	\
-	apt-mark auto '.*' > /dev/null; \
-	apt-mark manual $savedAptMark > /dev/null; \
-	find /usr/local -type f -executable -not \( -name '*tkinter*' \) -exec ldd '{}' ';' \
-		| awk '/=>/ { print $(NF-1) }' \
-		| sort -u \
-		| xargs -r dpkg-query --search \
-		| cut -d: -f1 \
-		| sort -u \
-		| xargs -r apt-mark manual \
-	; \
-	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
-	\
-	cd /; \
-	rm -r /usr/src/ruby; \
-# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
-	ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))'; \
-	gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/; \
-# verify we have no "ruby" packages installed
-	! dpkg -l | grep -i ruby; \
-	[ "$(command -v ruby)" = '/usr/local/bin/ruby' ]; \
-# rough smoke test
-	ruby --version; \
-	gem --version; \
-	bundle --version
-
-# don't create ".bundle" in all our apps
-ENV GEM_HOME /usr/local/bundle
-ENV BUNDLE_SILENCE_ROOT_WARNING=1 \
-	BUNDLE_APP_CONFIG="$GEM_HOME"
-ENV PATH $GEM_HOME/bin:$PATH
-# adjust permissions of a few directories for running "gem install" as an arbitrary user
-RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
-
-CMD [ "irb" ]