matth-x · jeremypoulter · Sep 20, 2026
diff --git a/.github/workflows/pio.yml b/.github/workflows/pio.yml
@@ -16,8 +16,12 @@ jobs:
 
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         example: [examples/ESP/main.cpp, examples/ESP-TLS/main.cpp]
+        # "pinned" keeps the ArduinoJson version pinned in platformio.ini (currently v6.20.1); "v7" overrides it to
+        # verify ArduinoJson v7 compatibility as well
+        arduinojson: [pinned, v7]
 
     steps:
     - uses: actions/checkout@v4
@@ -42,6 +46,11 @@ jobs:
     - name: Install library dependencies
       run: pio pkg install
     - name: Run PlatformIO
-      run: pio ci --lib="." --project-conf=platformio.ini ${{ matrix.dashboard-extra }}
+      run: |
+        if [ "${{ matrix.arduinojson }}" = "v7" ]; then
+          pio ci --lib="." --project-conf=platformio.ini -O "lib_deps=bblanchon/ArduinoJson@7.4.3" ${{ matrix.dashboard-extra }}
+        else
+          pio ci --lib="." --project-conf=platformio.ini ${{ matrix.dashboard-extra }}
+        fi
       env:
         PLATFORMIO_CI_SRC: ${{ matrix.example }}
diff --git a/.github/workflows/platformless.yml b/.github/workflows/platformless.yml
@@ -14,8 +14,24 @@ on:
 jobs:
 
   compile-platform:
-    name: Compile (no linking)
+    name: Compile (no linking, ArduinoJson ${{ matrix.arduinojson-version }})
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arduinojson-version: v6.19.4
+            arduinojson-url: https://github.com/bblanchon/ArduinoJson/releases/download/v6.19.4/ArduinoJson-v6.19.4.h
+            # ArduinoJson v6 doesn't emit any deprecation warnings for the API used here, so keep treating warnings as errors
+            werror-flag: -Werror
+          - arduinojson-version: v7.4.3
+            arduinojson-url: https://github.com/bblanchon/ArduinoJson/releases/download/v7.4.3/ArduinoJson-v7.4.3.h
+            # ArduinoJson v7 deprecates containsKey()/DynamicJsonDocument/StaticJsonDocument (still fully functional, kept
+            # intentionally for now to preserve v6 presence-check semantics) and, worse, JSON_OBJECT_SIZE/JSON_ARRAY_SIZE
+            # unconditionally emit a "#pragma GCC warning" that cannot be suppressed via any -Wno-* flag. Since this codebase
+            # still calls those macros (harmlessly, as a buffer-size hint v7 no longer needs) in ~50 files, -Werror is dropped
+            # for this leg rather than doing an invasive, version-branched rewrite of every call site.
+            werror-flag: ""
     steps:
     - name: Check out repository code
       uses: actions/checkout@v3
@@ -27,6 +43,6 @@ jobs:
         g++ --version
         echo "g++ version must be 9.4.0"
     - name: Get ArduinoJson
-      run: wget -Uri https://github.com/bblanchon/ArduinoJson/releases/download/v6.19.4/ArduinoJson-v6.19.4.h -O ./src/ArduinoJson.h
+      run: wget -Uri ${{ matrix.arduinojson-url }} -O ./src/ArduinoJson.h
     - name: Compile
-      run: g++ -c -std=c++11 -I ./src $(find ./src -type f -iregex ".*\.cpp") -DMO_PLATFORM=MO_PLATFORM_NONE -Wall -Wextra -Wno-unused-parameter -Wno-redundant-move -Werror
+      run: g++ -c -std=c++11 -I ./src $(find ./src -type f -iregex ".*\.cpp") -DMO_PLATFORM=MO_PLATFORM_NONE -Wall -Wextra -Wno-unused-parameter -Wno-redundant-move ${{ matrix.werror-flag }}
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -14,8 +14,16 @@ on:
 jobs:
 
   compile-and-run:
-    name: Automated Tests
+    name: Automated Tests (ArduinoJson ${{ matrix.arduinojson-version }})
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arduinojson-version: v6.21.3
+            arduinojson-url: https://github.com/bblanchon/ArduinoJson/releases/download/v6.21.3/ArduinoJson-v6.21.3.h
+          - arduinojson-version: v7.4.3
+            arduinojson-url: https://github.com/bblanchon/ArduinoJson/releases/download/v7.4.3/ArduinoJson-v7.4.3.h
     steps:
     - name: Check out repository code
       uses: actions/checkout@v3
@@ -33,7 +41,7 @@ jobs:
         g++ --version
         echo "g++ version must be 9.4.0"
     - name: Get ArduinoJson
-      run: wget -Uri https://github.com/bblanchon/ArduinoJson/releases/download/v6.21.3/ArduinoJson-v6.21.3.h -O ./src/ArduinoJson.h
+      run: wget -Uri ${{ matrix.arduinojson-url }} -O ./src/ArduinoJson.h
     - name: Generate CMake build files
       run: cmake -S . -B ./build -DMO_BUILD_UNIT_MBEDTLS=True
     - name: Compile

diff --git a/src/MicroOcpp/Core/Memory.cpp b/src/MicroOcpp/Core/Memory.cpp
@@ -92,6 +92,7 @@ namespace Memory {
 
 void* (*malloc_override)(size_t);
 void (*free_override)(void*);
+void* (*realloc_override)(void*, size_t);
 
 }
 }
@@ -103,6 +104,10 @@ void mo_mem_set_malloc_free(void* (*malloc_override)(size_t), void (*free_overri
     MicroOcpp::Memory::free_override = free_override;
 }
 
+void mo_mem_set_realloc(void* (*realloc_override)(void*, size_t)) {
+    MicroOcpp::Memory::realloc_override = realloc_override;
+}
+
 void *mo_mem_malloc(const char *tag, size_t size) {
     MO_DBG_VERBOSE("malloc %zu B (%s)", size, tag ? tag : "unspecified");
 
@@ -152,6 +157,42 @@ void mo_mem_free(void* ptr) {
     }
 }
 
+void *mo_mem_realloc(const char *tag, void *ptr, size_t size) {
+    MO_DBG_VERBOSE("realloc %zu B (%s)", size, tag ? tag : "unspecified");
+
+    #if MO_ENABLE_HEAP_PROFILER
+    if (ptr) {
+        auto blockInfo = memBlocks.find(ptr);
+        if (blockInfo != memBlocks.end()) {
+            auto tagInfo = memTags.find(blockInfo->second.tag);
+            if (tagInfo != memTags.end()) {
+                tagInfo->second -= blockInfo->second.size;
+            }
+            memTotal -= blockInfo->second.size;
+            memBlocks.erase(blockInfo);
+        }
+    }
+    #endif
+
+    void *new_ptr;
+    if (realloc_override) {
+        new_ptr = realloc_override(ptr, size);
+    } else {
+        new_ptr = realloc(ptr, size);
+    }
+
+    #if MO_ENABLE_HEAP_PROFILER
+    if (new_ptr) {
+        memBlocks.emplace(new_ptr, MemBlockInfo(new_ptr, tag, size));
+
+        memTotal += size;
+        memTotalMax = std::max(memTotalMax, memTotal);
+    }
+    #endif
+
+    return new_ptr;
+}
+
 #endif //MO_OVERRIDE_ALLOCATION
 
 #if MO_OVERRIDE_ALLOCATION && MO_ENABLE_HEAP_PROFILER
@@ -310,17 +351,21 @@ String makeString(const char *tag, const char *val) {
 }
 
 JsonDoc initJsonDoc(const char *tag, size_t capacity) {
-#if MO_OVERRIDE_ALLOCATION
+#if MO_OVERRIDE_ALLOCATION && ARDUINOJSON_VERSION_MAJOR < 7
     return JsonDoc(capacity, ArduinoJsonAllocator(tag));
 #else
+    //ArduinoJson >= v7 wraps TAllocator in a process-wide singleton (see AllocatorAdapter)
+    //and therefore doesn't support passing a per-call allocator instance (i.e. a memory tag) anymore
+    (void)tag;
     return JsonDoc(capacity);
 #endif
 }
 
 std::unique_ptr<JsonDoc> makeJsonDoc(const char *tag, size_t capacity) {
-#if MO_OVERRIDE_ALLOCATION
+#if MO_OVERRIDE_ALLOCATION && ARDUINOJSON_VERSION_MAJOR < 7
     return std::unique_ptr<JsonDoc>(new JsonDoc(capacity, ArduinoJsonAllocator(tag)));
 #else
+    (void)tag;
     return std::unique_ptr<JsonDoc>(new JsonDoc(capacity));
 #endif
 }

diff --git a/src/MicroOcpp/Core/Memory.h b/src/MicroOcpp/Core/Memory.h
@@ -32,12 +32,18 @@ void *mo_mem_malloc(const char *tag, size_t size);
 
 void mo_mem_free(void* ptr);
 
+void mo_mem_set_realloc(void* (*realloc_override)(void*, size_t)); //pass custom realloc function to be used with the OCPP lib (needed because ArduinoJson >= v7 reallocates its JSON document buffer as it grows). If not set or NULL, defaults to standard realloc
+
+void *mo_mem_realloc(const char *tag, void *ptr, size_t size);
+
 #define MO_MALLOC mo_mem_malloc
 #define MO_FREE mo_mem_free
+#define MO_REALLOC mo_mem_realloc
 
 #else
 #define MO_MALLOC(TAG, SIZE) malloc(SIZE) //default malloc provided by host system
 #define MO_FREE(PTR) free(PTR)       //default free provided by host system
+#define MO_REALLOC(TAG, PTR, SIZE) realloc(PTR, SIZE) //default realloc provided by host system
 #endif //MO_OVERRIDE_ALLOCATION
 
 
@@ -358,6 +364,13 @@ class ArduinoJsonAllocator {
     void deallocate(void *ptr) {
         MO_FREE(ptr);
     }
+    void *reallocate(void *ptr, size_t new_size) {
+        #if MO_ENABLE_HEAP_PROFILER
+            return MO_REALLOC(tag, ptr, new_size);
+        #else
+            return MO_REALLOC(nullptr, ptr, new_size);
+        #endif
+    }
 };
 
 using JsonDoc = BasicJsonDocument<ArduinoJsonAllocator>;

diff --git a/src/MicroOcpp/Operations/ReserveNow.cpp b/src/MicroOcpp/Operations/ReserveNow.cpp
@@ -30,7 +30,7 @@ const char* ReserveNow::getOperationType(){
 
 void ReserveNow::processReq(JsonObject payload) {
     if (!payload.containsKey("connectorId") ||
-            payload["connectorId"] < 0 ||
+            payload["connectorId"].as<int>() < 0 ||
             !payload.containsKey("expiryDate") ||
             !payload.containsKey("idTag") ||
             //parentIdTag is optional

diff --git a/tests/SmartCharging.cpp b/tests/SmartCharging.cpp
@@ -555,7 +555,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_2_RELATIVE_TXDEF_24A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;
@@ -573,7 +573,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_0_ALT_SAME_ID);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     (*doc)["connectorId"] = 2;
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
@@ -592,7 +592,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_1_ABSOLUTE_LIMIT_16A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;
@@ -615,7 +615,7 @@ TEST_CASE( "SmartCharging" ) {
                         StaticJsonDocument<2048> raw;
                         deserializeJson(raw, SCPROFILE_1_ABSOLUTE_LIMIT_16A);
                         auto doc = makeJsonDoc("UnitTests", 2048);
-                        *doc = raw[3];
+                        doc->set(raw[3]);
                         return doc;},
                     [&checkProcessed] (JsonObject response) {
                         checkProcessed = true;
@@ -637,7 +637,7 @@ TEST_CASE( "SmartCharging" ) {
                         StaticJsonDocument<2048> raw;
                         deserializeJson(raw, SCPROFILE_5_VALID_UNTIL_2022_16A);
                         auto doc = makeJsonDoc("UnitTests", 2048);
-                        *doc = raw[3];
+                        doc->set(raw[3]);
                         return doc;},
                     [&checkProcessed] (JsonObject response) {
                         checkProcessed = true;
@@ -661,7 +661,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_2_RELATIVE_TXDEF_24A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     (*doc)["csChargingProfiles"]["stackLevel"] = MO_ChargeProfileMaxStackLevel;
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
@@ -680,7 +680,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_2_RELATIVE_TXDEF_24A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     (*doc)["csChargingProfiles"]["stackLevel"] = MO_ChargeProfileMaxStackLevel + 1;
                     return doc;},
                 [] (JsonObject) { }, //ignore conf
@@ -706,7 +706,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_2_RELATIVE_TXDEF_24A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     JsonArray chargingSchedulePeriod = (*doc)["csChargingProfiles"]["chargingSchedule"]["chargingSchedulePeriod"];
                     chargingSchedulePeriod.clear();
                     for (size_t i = 0; i < MO_ChargingScheduleMaxPeriods; i++) {
@@ -731,7 +731,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_2_RELATIVE_TXDEF_24A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     JsonArray chargingSchedulePeriod = (*doc)["csChargingProfiles"]["chargingSchedule"]["chargingSchedulePeriod"];
                     chargingSchedulePeriod.clear();
                     for (size_t i = 0; i < MO_ChargingScheduleMaxPeriods + 1; i++) {
@@ -767,7 +767,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_0);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;
@@ -785,7 +785,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_1_ABSOLUTE_LIMIT_16A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;
@@ -807,7 +807,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_0);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;
@@ -825,7 +825,7 @@ TEST_CASE( "SmartCharging" ) {
                     StaticJsonDocument<2048> raw;
                     deserializeJson(raw, SCPROFILE_1_ABSOLUTE_LIMIT_16A);
                     auto doc = makeJsonDoc("UnitTests", 2048);
-                    *doc = raw[3];
+                    doc->set(raw[3]);
                     return doc;},
                 [&checkProcessed] (JsonObject response) {
                     checkProcessed = true;