diff --git a/include/wx/longlong.h b/include/wx/longlong.h
index 27cf9e8d1a..e8c399960b 100644
--- a/include/wx/longlong.h
+++ b/include/wx/longlong.h
@@ -164,8 +164,10 @@ public:
         return (long)m_ll;
     }
 
+#if wxABI_VERSION >= 20602
         // convert to double
     double ToDouble() const { return m_ll; }
+#endif // ABI >= 2.6.2
 
     // don't provide implicit conversion to wxLongLong_t or we will have an
     // ambiguity for all arithmetic operations
@@ -593,8 +595,10 @@ public:
         return (long)m_lo;
     }
 
+#if wxABI_VERSION >= 20602
         // convert to double
     double ToDouble() const;
+#endif // ABI >= 2.6.2
 
     // operations
         // addition