diff --git a/include/fmt/format.h b/include/fmt/format.h
index 1fc57de1..baebcff0 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -272,6 +272,12 @@ FMT_END_NAMESPACE
 #  define FMT_DEPRECATED_NUMERIC_ALIGN 0
 #endif
 
+#ifdef __cpp_ref_qualifiers
+  #  define FMT_METHOD_REF_QUALIFIER &
+#else
+  #  define FMT_METHOD_REF_QUALIFIER
+#endif
+
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
@@ -828,7 +834,7 @@ struct FMT_EXTERN_TEMPLATE_API uint128_wrapper {
   uint64_t high() const FMT_NOEXCEPT { return uint64_t(internal_ >> 64); }
   uint64_t low() const FMT_NOEXCEPT { return uint64_t(internal_); }
 
-  uint128_wrapper& operator+=(uint64_t n) & FMT_NOEXCEPT {
+  uint128_wrapper& operator+=(uint64_t n) FMT_METHOD_REF_QUALIFIER FMT_NOEXCEPT {
     internal_ += n;
     return *this;
   }
@@ -842,7 +848,7 @@ struct FMT_EXTERN_TEMPLATE_API uint128_wrapper {
   uint64_t high() const FMT_NOEXCEPT { return high_; }
   uint64_t low() const FMT_NOEXCEPT { return low_; }
 
-  uint128_wrapper& operator+=(uint64_t n) & FMT_NOEXCEPT {
+  uint128_wrapper& operator+=(uint64_t n) FMT_METHOD_REF_QUALIFIER FMT_NOEXCEPT {
 #  if defined(_MSC_VER) && defined(_M_X64)
     unsigned char carry = _addcarry_u64(0, low_, n, &low_);
     _addcarry_u64(carry, high_, 0, &high_);