diff --git a/mdbx.h b/mdbx.h
index c43c0c46..bbfe68c5 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -581,7 +581,8 @@ typedef mode_t mdbx_mode_t;
 extern "C" {
 #endif
 
-/* MDBX version 0.14.x */
+/* MDBX version 0.14.x, but it is unstable/under-development yet. */
+#define MDBX_VERSION_UNSTABLE
 #define MDBX_VERSION_MAJOR 0
 #define MDBX_VERSION_MINOR 14
 
diff --git a/src/version.c.in b/src/version.c.in
index 5c585eae..fdbfcb28 100644
--- a/src/version.c.in
+++ b/src/version.c.in
@@ -3,11 +3,16 @@
 
 #include "internals.h"
 
-#if MDBX_VERSION_MAJOR != ${MDBX_VERSION_MAJOR} || MDBX_VERSION_MINOR != ${MDBX_VERSION_MINOR}
+#if !defined(MDBX_VERSION_UNSTABLE) &&                                                                                 \
+    (MDBX_VERSION_MAJOR != ${MDBX_VERSION_MAJOR} || MDBX_VERSION_MINOR != ${MDBX_VERSION_MINOR})
 #error "API version mismatch! Had `git fetch --tags` done?"
 #endif
 
-static const char sourcery[] = MDBX_STRINGIFY(MDBX_BUILD_SOURCERY);
+static const char sourcery[] =
+#ifdef MDBX_VERSION_UNSTABLE
+    "UNSTABLE@"
+#endif
+    MDBX_STRINGIFY(MDBX_BUILD_SOURCERY);
 
 __dll_export
 #ifdef __attribute_used__