diff --git a/CMakeLists.txt b/CMakeLists.txt
index 37dcd1ac0..97acd0c3d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -329,7 +329,10 @@ if("${CMAKE_BUILD_TYPE}" STREQUAL "Debug")
     if(MSVC)
         set(EXE_CFLAGS "${EXE_CFLAGS} /w")
     else()
-        set(EXE_CFLAGS "${EXE_CFLAGS} -Werror -Wall -Werror=implicit-fallthrough")
+        set(EXE_CFLAGS "${EXE_CFLAGS} -Werror -Wall")
+        if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 7.0)
+            set(EXE_CFLAGS "${EXE_CFLAGS} -Werror=implicit-fallthrough")
+        endif()
     endif()
 endif()
 
diff --git a/src/util_base.hpp b/src/util_base.hpp
index 1c665bf93..da1d3bf23 100644
--- a/src/util_base.hpp
+++ b/src/util_base.hpp
@@ -68,7 +68,7 @@ static inline void zig_assert(bool ok, const char *file, int line, const char *f
 #define ZIG_FALLTHROUGH
 #elif defined(__clang__)
 #define ZIG_FALLTHROUGH [[clang::fallthrough]]
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) && __GNUC__ >= 7
 #define ZIG_FALLTHROUGH __attribute__((fallthrough))
 #else
 #define ZIG_FALLTHROUGH