diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 643379e7e429dcdac53ae38592eba953013b9b8b..a340693cda4c95ed49ba6b37c6f2f8b30ef88eb5 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,7 +14,7 @@ linters:
     - golangci-lint run
 
 unit tests:
-  image: golang:1.21.4
+  image: golang:1.21.5
   stage: test
   script:
     - go version
@@ -23,7 +23,7 @@ unit tests:
   coverage: '/total:\s+\(statements\)\s+(\d+.\d+\%)/'
 
 govulncheck:
-  image: golang:1.21.4
+  image: golang:1.21.5
   stage: test
   script:
     - go version
diff --git a/.golangci.yml b/.golangci.yml
index a31b66b24000f23ec82f765c828a26cf2bef07bd..bbcffe769d2a44cb772c1595ad69f69abf8fd2d6 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -27,3 +27,4 @@ linters:
     - misspell
     - staticcheck
     - unused
+    - gosimple
diff --git a/deployment/ci/Dockerfile b/deployment/ci/Dockerfile
index 6e562cf2eb25ed1ffc3066b03b2be6f9bc357ac8..95ea1d32cfac5da40da61b5ba094658182177cc8 100644
--- a/deployment/ci/Dockerfile
+++ b/deployment/ci/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.21.4-alpine3.17 as builder
+FROM golang:1.21.5-alpine3.17 as builder
 
 RUN apk add git
 
diff --git a/deployment/compose/Dockerfile b/deployment/compose/Dockerfile
index 751616b3003b12835a0e05b4575ac8ddcd8de314..a04fc48ae42a57f788ca6e33f8bf3b67bc29b1bd 100644
--- a/deployment/compose/Dockerfile
+++ b/deployment/compose/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.21.4
+FROM golang:1.21.5
 
 RUN go install github.com/ysmood/kit/cmd/guard@v0.25.11
 
diff --git a/go.mod b/go.mod
index 63d8ed1ce4ccb48e5cfd8bbf2bebcb384833a681..893ea2f267b5c4a136a356576a04528ffb4502ec 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module gitlab.eclipse.org/eclipse/xfsc/tsa/signer
 
-go 1.20
+go 1.21
 
 require (
 	github.com/hashicorp/vault/api v1.9.2