diff --git a/include/wx/buffer.h b/include/wx/buffer.h
index 51c837336f..a47a3e2cc7 100644
--- a/include/wx/buffer.h
+++ b/include/wx/buffer.h
@@ -111,6 +111,7 @@ private:                                                                    \
     chartype *m_str;                                                        \
 }
 
+#if wxABI_VERSION >= 20804
 // needed for wxString::char_str() and wchar_str()
 #define DEFINE_WRITABLE_BUFFER(classname, baseclass, chartype)              \
 class WXDLLIMPEXP_BASE classname : public baseclass                         \
@@ -121,14 +122,19 @@ public:                                                                     \
                                                                             \
     operator chartype*() { return this->data(); }                           \
 }
+#endif // wxABI_VERSION >= 20804
 
 DEFINE_BUFFER(wxCharBuffer, char, wxStrdupA);
+#if wxABI_VERSION >= 20804
 DEFINE_WRITABLE_BUFFER(wxWritableCharBuffer, wxCharBuffer, char);
+#endif
 
 #if wxUSE_WCHAR_T
 
 DEFINE_BUFFER(wxWCharBuffer, wchar_t, wxStrdupW);
+#if wxABI_VERSION >= 20804
 DEFINE_WRITABLE_BUFFER(wxWritableWCharBuffer, wxWCharBuffer, wchar_t);
+#endif
 
 #endif // wxUSE_WCHAR_T
 
diff --git a/include/wx/string.h b/include/wx/string.h
index 0455a59df1..1c5f303b90 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -836,6 +836,7 @@ public:
     // identical to c_str(), for MFC compatibility
     const wxChar* GetData() const { return c_str(); }
 
+#if wxABI_VERSION >= 20804
     // conversion to *non-const* multibyte or widestring buffer; modifying
     // returned buffer won't affect the string, these methods are only useful
     // for passing values to const-incorrect functions
@@ -844,6 +845,7 @@ public:
 #if wxUSE_WCHAR_T
     wxWritableWCharBuffer wchar_str() const { return wc_str(wxConvLibc); }
 #endif
+#endif // wxABI_VERSION >= 20804
 
     // conversion to/from plain (i.e. 7 bit) ASCII: this is useful for
     // converting numbers or strings which are certain not to contain special