3 files changed, 39 insertions, 21 deletions
diff --git a/Master/texmf-dist/source/generic/tex4ht/ChangeLog b/Master/texmf-dist/source/generic/tex4ht/ChangeLog
index 108cca0f50d..caa6abe8c55 100644
--- a/Master/texmf-dist/source/generic/tex4ht/ChangeLog
+++ b/Master/texmf-dist/source/generic/tex4ht/ChangeLog
@@ -1,3 +1,9 @@
+2021-07-05  Michal Hoftich  <michal.h21@gmail.com>
+
+	* tex4ht-4ht.tex (biblatex.4ht): updated redefinitions of \MakeUppercase and
+	\MakeLowercase to use the current code from LaTeX kernel. Also inserted
+	BibLaTeX hooks for these commands.
+
 2021-07-04  Karl Berry  <karl@freefriends.org>
 
 	* tex4ht-4ht.tex (showfonts.4ht, subcaption.4ht, subscript.4ht,
diff --git a/Master/texmf-dist/source/generic/tex4ht/tex4ht-4ht.tex b/Master/texmf-dist/source/generic/tex4ht/tex4ht-4ht.tex
index 3affa4ce045..a3071442679 100644
--- a/Master/texmf-dist/source/generic/tex4ht/tex4ht-4ht.tex
+++ b/Master/texmf-dist/source/generic/tex4ht/tex4ht-4ht.tex
@@ -1,4 +1,4 @@
-% $Id: tex4ht-4ht.tex 966 2021-07-04 16:13:49Z karl $
+% $Id: tex4ht-4ht.tex 967 2021-07-05 18:46:07Z michal_h21 $
 % tex tex4ht-4ht   or   ht tex tex4ht-4ht
 %
 % Copyright 2009-2021 TeX Users Group    
@@ -2152,18 +2152,24 @@ mechanism for ifthenelse.
 % MakeUppercase is redefined by tex4ht, biblatex tries to redefine it as well, but it relies on original 
 % LaTeX version:
 \DeclareRobustCommand{\MakeUppercase}[1]{{%
-    \def\i{I}\def\j{J}%
-    \def\reserved@a##1##2{\let##1##2\reserved@a}%
-    \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
-    \protected@edef\reserved@a{\uppercase{#1}}%
-    \reserved@a
+  \def\i{I}\def\j{J}%
+  \def\reserved@a##1##2{\let##1##2\reserved@a}%
+  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
+  \let\UTF@two@octets@noexpand\@empty
+  \let\UTF@three@octets@noexpand\@empty
+  \let\UTF@four@octets@noexpand\@empty
+  \blx@hook@uc\protected@edef\reserved@a{\uppercase{#1}}%
+  \reserved@a
 }}
 % Same applies also for \MakeLowercase
 \DeclareRobustCommand{\MakeLowercase}[1]{{%
-    \def\reserved@a##1##2{\let##2##1\reserved@a}%
-    \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
-    \protected@edef\reserved@a{\lowercase{#1}}%
-    \reserved@a
+  \def\reserved@a##1##2{\let##2##1\reserved@a}%
+  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
+  \let\UTF@two@octets@noexpand\@empty
+  \let\UTF@three@octets@noexpand\@empty
+  \let\UTF@four@octets@noexpand\@empty
+  \blx@hook@lc\protected@edef\reserved@a{\lowercase{#1}}%
+  \reserved@a
 }}
 
 % I don't really understand this, but language processing is broken by default
diff --git a/Master/texmf-dist/tex/generic/tex4ht/biblatex.4ht b/Master/texmf-dist/tex/generic/tex4ht/biblatex.4ht
index f8250afbc6e..5d8a19ce0cf 100644
--- a/Master/texmf-dist/tex/generic/tex4ht/biblatex.4ht
+++ b/Master/texmf-dist/tex/generic/tex4ht/biblatex.4ht
@@ -1,4 +1,4 @@
-% biblatex.4ht (2021-03-02-13:43), generated from tex4ht-4ht.tex
+% biblatex.4ht (2021-07-05-13:41), generated from tex4ht-4ht.tex
 % Copyright 2007-2009 Eitan M. Gurari
 % Copyright 2009-2021 TeX Users Group
 %
@@ -17,7 +17,7 @@
 %
 % If you modify this program, changing the
 % version identification would be appreciated.
-\immediate\write-1{version 2021-03-02-13:43}
+\immediate\write-1{version 2021-07-05-13:41}
 
    \def\make:blx:ver#1.#2#3\relax{%
    %\ifdim#1pt< 3pt \xdef\blx:ver:no{2}\else\xdef\blx:ver:no{3}\fi%
@@ -209,18 +209,24 @@
 % MakeUppercase is redefined by tex4ht, biblatex tries to redefine it as well, but it relies on original
 % LaTeX version:
 \DeclareRobustCommand{\MakeUppercase}[1]{{%
-    \def\i{I}\def\j{J}%
-    \def\reserved@a##1##2{\let##1##2\reserved@a}%
-    \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
-    \protected@edef\reserved@a{\uppercase{#1}}%
-    \reserved@a
+  \def\i{I}\def\j{J}%
+  \def\reserved@a##1##2{\let##1##2\reserved@a}%
+  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
+  \let\UTF@two@octets@noexpand\@empty
+  \let\UTF@three@octets@noexpand\@empty
+  \let\UTF@four@octets@noexpand\@empty
+  \blx@hook@uc\protected@edef\reserved@a{\uppercase{#1}}%
+  \reserved@a
 }}
 % Same applies also for \MakeLowercase
 \DeclareRobustCommand{\MakeLowercase}[1]{{%
-    \def\reserved@a##1##2{\let##2##1\reserved@a}%
-    \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
-    \protected@edef\reserved@a{\lowercase{#1}}%
-    \reserved@a
+  \def\reserved@a##1##2{\let##2##1\reserved@a}%
+  \expandafter\reserved@a\@uclclist\reserved@b{\reserved@b\@gobble}%
+  \let\UTF@two@octets@noexpand\@empty
+  \let\UTF@three@octets@noexpand\@empty
+  \let\UTF@four@octets@noexpand\@empty
+  \blx@hook@lc\protected@edef\reserved@a{\lowercase{#1}}%
+  \reserved@a
 }}
 
 % I don't really understand this, but language processing is broken by default