diff --git a/src/cppstd/cppstd.cppm b/src/cppstd/cppstd.cppm
index ceb0876..024124c 100644
--- a/src/cppstd/cppstd.cppm
+++ b/src/cppstd/cppstd.cppm
@@ -910,7 +910,7 @@ export using std::move_only_function;
 // ADL can't find them through `import cppstd;`. Non-portable but needed for
 // libstdc++ — libc++ uses different iterator types, so this block is a no-op
 // elsewhere (guarded by __GLIBCXX__).
-#if defined(__GLIBCXX__) && __GLIBCXX__ <= 20260209
+#if defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE <= 15
 namespace __gnu_cxx
 {
 export using __gnu_cxx::operator==;