diff --git a/Dockerfile b/Dockerfile
index 70a97a41..f203d58b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM fpco/stack-build:lts-14.20
+FROM fpco/stack-build:lts-14.21
 
 # Install all necessary Ubuntu packages
 RUN apt-get update && apt-get install -y python3-pip libgmp-dev libmagic-dev libtinfo-dev libzmq3-dev libcairo2-dev libpango1.0-dev libblas-dev liblapack-dev gcc g++ && \
diff --git a/stack.yaml b/stack.yaml
index 884ad97d..827ce7ff 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-14.20
+resolver: lts-14.21
 
 flags: {}
 packages: