diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index bdba08455db..876cbfb97d8 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -96,17 +96,18 @@ LANG_RELEASE_MATRIX = {
             ('v1.17.1', ReleaseInfo(testcases_file='cxx__v1.0.1')),
             ('v1.18.0', ReleaseInfo(testcases_file='cxx__v1.0.1')),
             ('v1.19.0', ReleaseInfo(testcases_file='cxx__v1.0.1')),
-            ('v1.20.0', ReleaseInfo()),
-            ('v1.21.4', ReleaseInfo()),
-            ('v1.22.0', ReleaseInfo()),
-            ('v1.22.1', ReleaseInfo()),
-            ('v1.23.0', ReleaseInfo()),
-            ('v1.24.0', ReleaseInfo()),
-            ('v1.25.0', ReleaseInfo()),
-            ('v1.26.0', ReleaseInfo()),
-            ('v1.27.3', ReleaseInfo()),
-            ('v1.30.0', ReleaseInfo()),
-            ('v1.31.1', ReleaseInfo()),
+            ('v1.20.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.21.4', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.22.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.22.1', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.23.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.24.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.25.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.26.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.27.3', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.30.0', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.31.1', ReleaseInfo(testcases_file='cxx__v1.31.1')),
+            ('v1.32.0', ReleaseInfo()),
         ]),
     'go':
         OrderedDict([
diff --git a/tools/interop_matrix/testcases/cxx__master b/tools/interop_matrix/testcases/cxx__master
index 5739d6649e7..e5d317f07bb 100755
--- a/tools/interop_matrix/testcases/cxx__master
+++ b/tools/interop_matrix/testcases/cxx__master
@@ -1,22 +1,22 @@
 #!/bin/bash
 # DO NOT MODIFY
 # This file is generated by run_interop_tests.py/create_testcases.sh
-echo "Testing ${docker_image:=grpc_interop_cxx:f5a2f91d-342a-4bc8-a5ca-eb113dd3a8a2}"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
-docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"
+echo "Testing ${docker_image:=grpc_interop_cxx:eadcc0fd-5683-411b-aed5-084fbb3159ee}"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "cmake/build/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"
diff --git a/tools/interop_matrix/testcases/cxx__v1.31.1 b/tools/interop_matrix/testcases/cxx__v1.31.1
new file mode 100755
index 00000000000..5739d6649e7
--- /dev/null
+++ b/tools/interop_matrix/testcases/cxx__v1.31.1
@@ -0,0 +1,22 @@
+#!/bin/bash
+# DO NOT MODIFY
+# This file is generated by run_interop_tests.py/create_testcases.sh
+echo "Testing ${docker_image:=grpc_interop_cxx:f5a2f91d-342a-4bc8-a5ca-eb113dd3a8a2}"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=large_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_unary --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=ping_pong --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=empty_stream --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=client_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=server_streaming --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_begin --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=cancel_after_first_response --use_tls=true"
+docker run -i --rm=true -w /var/local/git/grpc --net=host $docker_image bash -c "bins/opt/interop_client --server_host=grpc-test4.sandbox.googleapis.com --server_port=443 --test_case=timeout_on_sleeping_server --use_tls=true"