diff --git a/alpine/Dockerfile b/alpine/Dockerfile
index 1943a2d..4de387a 100644
--- a/alpine/Dockerfile
+++ b/alpine/Dockerfile
@@ -1,10 +1,10 @@
-FROM alpine:3.3
+FROM alpine:3.4
 
 # add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
 RUN adduser -D memcache
 
-ENV MEMCACHED_VERSION 1.4.27
-ENV MEMCACHED_SHA1 b5869038dc5f2dce24f3a62806eadfd64d58662e
+ENV MEMCACHED_VERSION 1.4.28
+ENV MEMCACHED_SHA256 ef847bba60301cc600f06a8c64bf91c6c3f65ca507462951f918963297bcb816
 
 RUN set -x \
 	&& apk add --no-cache --virtual .build-deps \
@@ -16,7 +16,7 @@ RUN set -x \
 		perl \
 		tar \
 	&& wget -O memcached.tar.gz "http://memcached.org/files/memcached-$MEMCACHED_VERSION.tar.gz" \
-	&& echo "$MEMCACHED_SHA1  memcached.tar.gz" | sha1sum -c - \
+	&& echo "$MEMCACHED_SHA256  memcached.tar.gz" | sha256sum -c - \
 	&& mkdir -p /usr/src/memcached \
 	&& tar -xzf memcached.tar.gz -C /usr/src/memcached --strip-components=1 \
 	&& rm memcached.tar.gz \
diff --git a/debian/Dockerfile b/debian/Dockerfile
index 3c0bfe4..3c3c598 100644
--- a/debian/Dockerfile
+++ b/debian/Dockerfile
@@ -7,8 +7,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 		libevent-2.0-5 \
 	&& rm -rf /var/lib/apt/lists/*
 
-ENV MEMCACHED_VERSION 1.4.27
-ENV MEMCACHED_SHA1 b5869038dc5f2dce24f3a62806eadfd64d58662e
+ENV MEMCACHED_VERSION 1.4.28
+ENV MEMCACHED_SHA256 ef847bba60301cc600f06a8c64bf91c6c3f65ca507462951f918963297bcb816
 
 RUN buildDeps=' \
 		gcc \
@@ -22,7 +22,7 @@ RUN buildDeps=' \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& wget -O memcached.tar.gz "http://memcached.org/files/memcached-$MEMCACHED_VERSION.tar.gz" \
-	&& echo "$MEMCACHED_SHA1  memcached.tar.gz" | sha1sum -c - \
+	&& echo "$MEMCACHED_SHA256  memcached.tar.gz" | sha256sum -c - \
 	&& mkdir -p /usr/src/memcached \
 	&& tar -xzf memcached.tar.gz -C /usr/src/memcached --strip-components=1 \
 	&& rm memcached.tar.gz \