diff --git a/unicodedomino_compat.def b/unicodedomino_compat.def
index f110a7445a7329129a365eb92e2dec96f347f757..61e2504f98209074f6b03c31773c74f043c038bc 100644
--- a/unicodedomino_compat.def
+++ b/unicodedomino_compat.def
@@ -44,3 +44,12 @@
    \the\numexpr\decode@UTFviii#2\relax})%
  }%
 \fi%
+
+% added in v1.2f 2018/10/05
+\ifx\UTFviii@two@octets@combine\@undefined%
+ % override message to give the byte in hex
+ \def\UTFviii@invalid@err#1{%
+  \PackageError{inputenc}{Invalid UTF-8 byte "\UTFviii@hexnumber{`#1}}%
+   \UTFviii@invalid@help%
+ }%
+\fi%
diff --git a/unicodedomino_kernel_cosmetics.def b/unicodedomino_kernel_cosmetics.def
index 41a9e6da464d77def6039d3cc57402ab3baa3255..fa39367910d37dbfe5cd7522439d047fb5b9fc5b 100644
--- a/unicodedomino_kernel_cosmetics.def
+++ b/unicodedomino_kernel_cosmetics.def
@@ -5,15 +5,6 @@
 %-
 % Improve error and warning formatting.
 
-%: merged, but ifx yet to see
-\ifx\UTFviii@check@three\@undefined%
- % override message to give the byte in hex
- \def\UTFviii@invalid@err#1{%
-  \PackageError{inputenc}{Invalid UTF-8 byte "\UTFviii@hexnumber{`#1}}%
-   \UTFviii@invalid@help%
- }%
-\fi%
-
 % override to format a UCS codepoint (hexadecimal notation) correctly
 \gdef\UTFviii@hexcodepoint#1{%
  \ifnum#1<16 U+000%