diff --git a/CMakeLists.txt b/CMakeLists.txt
index f324c0d..448e37c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,13 +1,31 @@
 cmake_minimum_required(VERSION 3.23)
 
+# Read the version from the public header so it stays the single source of truth.
+function(_zeus_expected_parse_header_version header result_var)
+    file(READ "${header}" _header)
+    foreach(_comp MAJOR MINOR PATCH)
+        string(REGEX MATCH "#define ZEUS_EXPECTED_VERSION_${_comp} ([0-9]+)" _match "${_header}")
+        set(_version "${_version}${CMAKE_MATCH_1}.")
+    endforeach()
+    string(REGEX REPLACE "\\.$" "" _version "${_version}")
+    set(${result_var} "${_version}" PARENT_SCOPE)
+endfunction()
+
+_zeus_expected_parse_header_version(
+    "${CMAKE_CURRENT_SOURCE_DIR}/include/zeus/expected.hpp"
+    _zeus_expected_header_version
+)
+
 project(
     zeus_expected
-    VERSION 1.3.3
+    VERSION ${_zeus_expected_header_version}
     DESCRIPTION "Backporting std::expected to C++17."
     HOMEPAGE_URL "https://github.com/zeus-cpp/expected"
     LANGUAGES CXX
 )
 
+unset(_zeus_expected_header_version)
+
 add_library(${PROJECT_NAME} INTERFACE)
 add_library(zeus::expected ALIAS ${PROJECT_NAME})
 
diff --git a/include/zeus/expected.hpp b/include/zeus/expected.hpp
index b0d3261..711f744 100644
--- a/include/zeus/expected.hpp
+++ b/include/zeus/expected.hpp
@@ -8,7 +8,7 @@
 
 #define ZEUS_EXPECTED_VERSION_MAJOR 1
 #define ZEUS_EXPECTED_VERSION_MINOR 3
-#define ZEUS_EXPECTED_VERSION_PATCH 3
+#define ZEUS_EXPECTED_VERSION_PATCH 4
 
 #if defined(_MSVC_LANG)
     #define ZEUS_EXPECTED_CPLUSPLUS _MSVC_LANG