diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 7f259f5..e89108e 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2449,6 +2449,25 @@
     tests/compat.sh
 }
 
+component_test_variable_ssl_in_out_buffer_len_CID_legacy () {
+    msg "build: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_DTLS_CONNECTION_ID (legacy) enabled (ASan build)"
+    scripts/config.py set MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH
+    scripts/config.py set MBEDTLS_SSL_DTLS_CONNECTION_ID
+    scripts/config.py set MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT 1
+
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+
+    msg "test: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_DTLS_CONNECTION_ID"
+    make test
+
+    msg "test: ssl-opt.sh, MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_DTLS_CONNECTION_ID enabled"
+    tests/ssl-opt.sh
+
+    msg "test: compat.sh, MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_DTLS_CONNECTION_ID enabled"
+    tests/compat.sh
+}
+
 component_test_ssl_alloc_buffer_and_mfl () {
     msg "build: default config with memory buffer allocator and MFL extension"
     scripts/config.py set MBEDTLS_MEMORY_BUFFER_ALLOC_C
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index c4628b0..36cb479 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -440,6 +440,14 @@
     requires_config_value_at_least "MBEDTLS_SSL_OUT_CONTENT_LEN" $1
 }
 
+CID_MODE=$( get_config_value_or_default "MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT" )
+
+requires_cid_compat() {
+    if [ "$CID_MODE" = "0" ]; then
+        SKIP_NEXT="YES"
+    fi
+}
+
 # skip next test if GnuTLS isn't available
 requires_gnutls() {
     if [ -z "${GNUTLS_AVAILABLE:-}" ]; then
@@ -2387,6 +2395,17 @@
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
+requires_config_enabled MBEDTLS_SSL_DTLS_CONNECTION_ID
+requires_cid_compat
+run_test    "Context serialization, client serializes, with CID (legacy)" \
+            "$P_SRV dtls=1 serialize=0 exchanges=2 cid=1 cid_val=dead" \
+            "$P_CLI dtls=1 serialize=1 exchanges=2 cid=1 cid_val=beef" \
+            0 \
+            -c "Deserializing connection..." \
+            -S "Deserializing connection..."
+
+
+requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
 run_test    "Context serialization, server serializes, CCM" \
             "$P_SRV dtls=1 serialize=1 exchanges=2" \
             "$P_CLI dtls=1 serialize=0 exchanges=2 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
@@ -2422,6 +2441,16 @@
             -C "Deserializing connection..." \
             -s "Deserializing connection..."
 
+requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
+requires_config_enabled MBEDTLS_SSL_DTLS_CONNECTION_ID
+requires_cid_compat
+run_test    "Context serialization, server serializes, with CID (legacy)" \
+            "$P_SRV dtls=1 serialize=1 exchanges=2 cid=1 cid_val=dead" \
+            "$P_CLI dtls=1 serialize=0 exchanges=2 cid=1 cid_val=beef" \
+            0 \
+            -C "Deserializing connection..." \
+            -s "Deserializing connection..."
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
 run_test    "Context serialization, both serialize, CCM" \
@@ -2461,6 +2490,17 @@
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
+requires_config_enabled MBEDTLS_SSL_DTLS_CONNECTION_ID
+requires_cid_compat
+run_test    "Context serialization, both serialize, with CID (legacy)" \
+            "$P_SRV dtls=1 serialize=1 exchanges=2 cid=1 cid_val=dead" \
+            "$P_CLI dtls=1 serialize=1 exchanges=2 cid=1 cid_val=beef" \
+            0 \
+            -c "Deserializing connection..." \
+            -s "Deserializing connection..."
+
+
+requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
 run_test    "Context serialization, re-init, client serializes, CCM" \
             "$P_SRV dtls=1 serialize=0 exchanges=2" \
             "$P_CLI dtls=1 serialize=2 exchanges=2 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
@@ -2498,6 +2538,16 @@
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
+requires_config_enabled MBEDTLS_SSL_DTLS_CONNECTION_ID
+requires_cid_compat
+run_test    "Context serialization, re-init, client serializes, with CID (legacy)" \
+            "$P_SRV dtls=1 serialize=0 exchanges=2 cid=1 cid_val=dead" \
+            "$P_CLI dtls=1 serialize=2 exchanges=2 cid=1 cid_val=beef" \
+            0 \
+            -c "Deserializing connection..." \
+            -S "Deserializing connection..."
+
+requires_config_enabled MBEDTLS_SSL_CONTEXT_SERIALIZATION
 run_test    "Context serialization, re-init, server serializes, CCM" \
             "$P_SRV dtls=1 serialize=2 exchanges=2" \
             "$P_CLI dtls=1 serialize=0 exchanges=2 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \