diff --git a/docker/alpine.Dockerfile b/docker/alpine.Dockerfile
index 64063a5a..ba0c1af4 100644
--- a/docker/alpine.Dockerfile
+++ b/docker/alpine.Dockerfile
@@ -1,11 +1,11 @@
-FROM alpine:3.12 as runtime
+FROM alpine:3.13 as runtime
 
 RUN \
   apk add --update --no-cache --force-overwrite \
     # core dependencies
     gc-dev gcc gmp-dev libatomic_ops libevent-static musl-dev pcre-dev \
     # stdlib dependencies
-    libxml2-dev openssl-dev openssl-libs-static tzdata yaml-dev zlib-static \
+    libxml2-dev openssl-libs-static tzdata yaml-static zlib-static \
     # dev tools
     make git
 
@@ -31,6 +31,6 @@ FROM runtime as build
 
 RUN \
   apk add --update --no-cache --force-overwrite \
-    llvm10-dev llvm10-static g++
+    llvm10-static g++
 
 CMD ["/bin/sh"]
diff --git a/linux/Dockerfile b/linux/Dockerfile
index 437a833e..1e15f4c1 100644
--- a/linux/Dockerfile
+++ b/linux/Dockerfile
@@ -43,7 +43,7 @@ RUN sed -i 's|--list -- "$@"|--list "$@"|' /usr/bin/ldd
 # Install dependencies
 RUN apk add --no-cache \
       # Statically-compiled llvm
-      llvm10-dev llvm10-static \
+      llvm10-static \
       # Static zlib, libyaml, libxml2, pcre, and libevent
       zlib-static yaml-static libxml2-dev pcre-dev libevent-static \
       # Build tools
diff --git a/linux/Makefile b/linux/Makefile
index d516aad8..ff6699ba 100644
--- a/linux/Makefile
+++ b/linux/Makefile
@@ -48,14 +48,14 @@ BUILD_ARGS_COMMON = $(DOCKER_BUILD_ARGS) \
 BUILD_ARGS64 = $(BUILD_ARGS_COMMON) \
                --build-arg previous_crystal_release=$(PREVIOUS_CRYSTAL_RELEASE_LINUX64_TARGZ)	\
                --build-arg debian_image=debian:10 \
-               --build-arg alpine_image=alpine:3.12 \
+               --build-arg alpine_image=alpine:3.13 \
                --build-arg musl_target=x86_64-linux-musl \
                --build-arg gnu_target=x86_64-unknown-linux-gnu
 
 BUILD_ARGS32 = $(BUILD_ARGS_COMMON) \
                --build-arg previous_crystal_release=$(PREVIOUS_CRYSTAL_RELEASE_LINUX32_TARGZ) \
                --build-arg debian_image=i386/debian:10 \
-               --build-arg alpine_image=i386/alpine:3.12 \
+               --build-arg alpine_image=i386/alpine:3.13 \
                --build-arg musl_target=i686-linux-musl \
                --build-arg gnu_target=i686-unknown-linux-gnu