diff --git a/.github/workflows/build-check.yaml b/.github/workflows/build-check.yaml
index 96545a251..cac9e56a9 100644
--- a/.github/workflows/build-check.yaml
+++ b/.github/workflows/build-check.yaml
@@ -127,6 +127,19 @@ jobs:
         if: always()
         run: kill ${{ steps.run-zenoh.outputs.zenohd-pid }}
 
+  unstable_build:
+    name: Check compilation with unstable API
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Build with unstable
+        run: |
+          sudo apt install -y ninja-build
+          Z_FEATURE_UNSTABLE_API=1 CMAKE_GENERATOR=Ninja make
+
+
   st_build:
     needs: zenoh_build
     name: Build and test in single thread on ubuntu-latest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0dfcd31fe..1cd4b89b6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -184,6 +184,7 @@ set(BATCH_UNICAST_SIZE 2048 CACHE STRING "Use this to override the maximum unica
 set(BATCH_MULTICAST_SIZE 2048 CACHE STRING "Use this to override the maximum multicast batch size")
 set(Z_CONFIG_SOCKET_TIMEOUT 100 CACHE STRING "Default socket timeout in milliseconds")
 
+set(Z_FEATURE_UNSTABLE_API 0 CACHE STRING "Toggle unstable Zenoh-C API")
 set(Z_FEATURE_PUBLICATION 1 CACHE STRING "Toggle publication feature")
 set(Z_FEATURE_SUBSCRIPTION 1 CACHE STRING "Toggle subscription feature")
 set(Z_FEATURE_QUERY 1 CACHE STRING "Toggle query feature")
@@ -208,6 +209,7 @@ set(Z_FEATURE_INTEREST 1 CACHE STRING "Toggle interest feature")
 
 add_compile_definitions("Z_BUILD_DEBUG=$<CONFIG:Debug>")
 message(STATUS "Building with feature confing:\n\
+* UNSTABLE_API: ${Z_FEATURE_UNSTABLE_API}\n\
 * MULTI-THREAD: ${Z_FEATURE_MULTI_THREAD}\n\
 * PUBLICATION: ${Z_FEATURE_PUBLICATION}\n\
 * SUBSCRIPTION: ${Z_FEATURE_SUBSCRIPTION}\n\
diff --git a/GNUmakefile b/GNUmakefile
index 217a64342..fcbbbb4d8 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -51,6 +51,7 @@ ZENOH_DEBUG?=0
 
 # Feature config toggle
 # Accepted values: 0, 1
+Z_FEATURE_UNSTABLE_API?=0
 Z_FEATURE_MULTI_THREAD?=1
 Z_FEATURE_PUBLICATION?=1
 Z_FEATURE_SUBSCRIPTION?=1
@@ -78,7 +79,7 @@ CROSSIMG_PREFIX=zenoh-pico_
 # - ARM:   old versions of dockcross/dockcross were creating some issues since they used an old GCC (4.8.3) which lacks <stdatomic.h> (even using -std=gnu11)
 
 CMAKE_OPT=-DZENOH_DEBUG=$(ZENOH_DEBUG) -DBUILD_EXAMPLES=$(BUILD_EXAMPLES) -DCMAKE_BUILD_TYPE=$(BUILD_TYPE) -DBUILD_TESTING=$(BUILD_TESTING) -DBUILD_MULTICAST=$(BUILD_MULTICAST)\
- -DZ_FEATURE_MULTI_THREAD=$(Z_FEATURE_MULTI_THREAD) -DZ_FEATURE_INTEREST=$(Z_FEATURE_INTEREST) \
+ -DZ_FEATURE_MULTI_THREAD=$(Z_FEATURE_MULTI_THREAD) -DZ_FEATURE_INTEREST=$(Z_FEATURE_INTEREST) -DZ_FEATURE_UNSTABLE_API=$(Z_FEATURE_UNSTABLE_API)\
  -DZ_FEATURE_PUBLICATION=$(Z_FEATURE_PUBLICATION) -DZ_FEATURE_SUBSCRIPTION=$(Z_FEATURE_SUBSCRIPTION) -DZ_FEATURE_QUERY=$(Z_FEATURE_QUERY) -DZ_FEATURE_QUERYABLE=$(Z_FEATURE_QUERYABLE)\
  -DZ_FEATURE_RAWETH_TRANSPORT=$(Z_FEATURE_RAWETH_TRANSPORT) -DFRAG_MAX_SIZE=$(FRAG_MAX_SIZE) -DBATCH_UNICAST_SIZE=$(BATCH_UNICAST_SIZE) -DBATCH_MULTICAST_SIZE=$(BATCH_MULTICAST_SIZE)\
  -DBUILD_INTEGRATION=$(BUILD_INTEGRATION) -DBUILD_TOOLS=$(BUILD_TOOLS) -DBUILD_SHARED_LIBS=$(BUILD_SHARED_LIBS) -H.
diff --git a/PackageConfig.cmake.in b/PackageConfig.cmake.in
index d3aa3d367..b84b6c3ec 100644
--- a/PackageConfig.cmake.in
+++ b/PackageConfig.cmake.in
@@ -17,6 +17,7 @@
 set(ZENOHPICO_BUILD_SHARED_LIBS @BUILD_SHARED_LIBS@)
 set(CMAKE_SYSTEM_NAME @CMAKE_SYSTEM_NAME@)
 
+set(ZENOHPICO_FEATURE_UNSTABLE_API @Z_FEATURE_UNSTABLE_API@)
 set(ZENOHPICO_FEATURE_MULTI_THREAD @Z_FEATURE_MULTI_THREAD@)
 set(ZENOHPICO_FEATURE_PUBLICATION @Z_FEATURE_PUBLICATION@)
 set(ZENOHPICO_FEATURE_SUBSCRIPTION @Z_FEATURE_SUBSCRIPTION@)
diff --git a/docs/conf.py b/docs/conf.py
index adaff5535..4ad571076 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -30,6 +30,7 @@
 language = 'c'
 c_autodoc_roots = ['../include/zenoh-pico/api/']
 c_autodoc_compilation_args = [
+    "-DZ_FEATURE_UNSTABLE_API=1",
     "-DZ_FEATURE_PUBLICATION=1",
     "-DZ_FEATURE_SUBSCRIPTION=1",
     "-DZ_FEATURE_QUERY=1",
diff --git a/include/zenoh-pico/api/types.h b/include/zenoh-pico/api/types.h
index 39dea8a86..1db2306c2 100644
--- a/include/zenoh-pico/api/types.h
+++ b/include/zenoh-pico/api/types.h
@@ -183,10 +183,14 @@ _Z_OWNED_TYPE_VALUE(_z_value_t, reply_err)
  * Represents the configuration used to configure a subscriber upon declaration :c:func:`z_declare_subscriber`.
  *
  * Members:
- *   z_reliability_t reliability: The subscription reliability value.
+ *   (unstable) z_reliability_t reliability: The subscription reliability value.
  */
 typedef struct {
+#ifdef Z_FEATURE_UNSTABLE_API
     z_reliability_t reliability;
+#else
+    uint8_t __dummy;  // Just to avoid empty structures that might cause undefined behavior
+#endif
 } z_subscriber_options_t;
 
 /**
diff --git a/src/api/api.c b/src/api/api.c
index 768efd4ba..53948ac93 100644
--- a/src/api/api.c
+++ b/src/api/api.c
@@ -1556,7 +1556,13 @@ void _z_subscriber_drop(_z_subscriber_t *sub) { _z_undeclare_and_clear_subscribe
 _Z_OWNED_FUNCTIONS_VALUE_NO_COPY_IMPL(_z_subscriber_t, subscriber, _z_subscriber_check, _z_subscriber_null,
                                       _z_subscriber_drop)
 
-void z_subscriber_options_default(z_subscriber_options_t *options) { options->reliability = Z_RELIABILITY_DEFAULT; }
+void z_subscriber_options_default(z_subscriber_options_t *options) {
+#if Z_FEATURE_UNSTABLE_API == 1
+    options->reliability = Z_RELIABILITY_DEFAULT;
+#else
+    options->__dummy = 0;
+#endif
+}
 
 int8_t z_declare_subscriber(z_owned_subscriber_t *sub, const z_loaned_session_t *zs, const z_loaned_keyexpr_t *keyexpr,
                             z_moved_closure_sample_t *callback, const z_subscriber_options_t *options) {
@@ -1599,7 +1605,11 @@ int8_t z_declare_subscriber(z_owned_subscriber_t *sub, const z_loaned_session_t
 
     _z_subinfo_t subinfo = _z_subinfo_default();
     if (options != NULL) {
+#if Z_FEATURE_UNSTABLE_API == 1
         subinfo.reliability = options->reliability;
+#else
+        subinfo.reliability = Z_RELIABILITY_DEFAULT;
+#endif
     }
     _z_subscriber_t int_sub =
         _z_declare_subscriber(zs, key, subinfo, callback->_this._val.call, callback->_this._val.drop, ctx);
diff --git a/zenohpico.pc b/zenohpico.pc
index 9d0772da5..82d230a15 100644
--- a/zenohpico.pc
+++ b/zenohpico.pc
@@ -3,6 +3,6 @@ prefix=/usr/local
 Name: zenohpico
 Description: 
 URL: 
-Version: 1.0.20240819dev
+Version: 1.0.20240822dev
 Cflags: -I${prefix}/include
 Libs: -L${prefix}/lib -lzenohpico