diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 483583d6c..616c5612b 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -12,7 +12,7 @@ on:
 jobs:
   ci_test_clang:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     steps:
       - uses: actions/checkout@v2
       - name: cmake
@@ -22,7 +22,7 @@ jobs:
 
   ci_test_gcc:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     steps:
       - uses: actions/checkout@v2
       - name: cmake
@@ -32,7 +32,7 @@ jobs:
 
   ci_static_analysis:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     strategy:
       matrix:
         target: [ci_clang_tidy, ci_cppcheck, ci_test_valgrind, ci_test_clang_sanitizer, ci_test_amalgamation, ci_clang_analyze, ci_cpplint, ci_cmake_flags, ci_single_binaries, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_infer]
@@ -45,7 +45,7 @@ jobs:
 
   ci_cmake_options:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     strategy:
       matrix:
         target: [ci_test_diagnostics, ci_test_noexceptions, ci_test_noimplicitconversions]
@@ -58,7 +58,7 @@ jobs:
 
   ci_test_coverage:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     steps:
       - uses: actions/checkout@v2
       - name: cmake
@@ -78,7 +78,7 @@ jobs:
 
   ci_test_compilers:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     strategy:
       matrix:
         compiler: [g++-4.8, g++-4.9, g++-5, g++-6, g++-7, g++-8, g++-9, g++-10, clang++-3.5, clang++-3.6, clang++-3.7, clang++-3.8, clang++-3.9, clang++-4.0, clang++-5.0, clang++-6.0, clang++-7, clang++-8, clang++-9, clang++-10, clang++-11, clang++-12, clang++-13, clang++-14]
@@ -91,7 +91,7 @@ jobs:
 
   ci_test_standards:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     strategy:
       matrix:
         standard: [11, 14, 17, 20]
@@ -105,7 +105,7 @@ jobs:
 
   ci_cuda_example:
     runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:latest
+    container: ghcr.io/nlohmann/json-ci:v2.3.0
     steps:
       - uses: actions/checkout@v2
       - name: cmake