diff --git a/ChangeLog b/ChangeLog
index 19967ac..1622079 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2021-10-11  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* src/configure (kdf_do): It can be overridden, now.
+
 2021-07-01  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* src/configure (CONFIG): Add KDF configuration.
diff --git a/NEWS b/NEWS
index e176059..31247d1 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,49 @@
 Gnuk NEWS - User visible changes
 
 
+* Major changes in Gnuk 1.2.19
+
+  Released 2021-10-12, by NIIBE Yutaka
+
+** KDF Data Object configuration
+KDF Data Object should be highly recommended for all configurations.
+Nevertheless, for backward compatibillity, in Gnuk 1.2, it is optional
+by default; It is up to user to configure KDF Data Object before
+importing private keys.  In this situation, it is not good to
+introduce new build-time option like --enable-always-require-kdf-do,
+because it might wrongly encourage use of Gnuk with no KDF Data Object
+setting, by confusion.  If needed, please run configure:
+
+  kdf_do=required ./configure --enable-factory-reset --target...
+
+or
+
+  kdf_do=optional ./configure --enable-factory-reset --target...
+
+Please note that such a use of variable by shell command line is not
+well supported by the configure script (for other variables), but
+override of kdf_do is needed in some situations.
+
+** Upgrade of Chopstx
+We use Chopstx 1.20.  This enables use with PC/SC for GNU/Linux
+emulation.
+
+
+* Major changes in Gnuk 1.2.18
+
+  Released 2021-04-02, by NIIBE Yutaka
+
+** GNU/Linux emulation bug fix
+This time, for GNU/Linux emulation, KDF Data Object is required before
+keygen and key import, really.
+
+** tool/upgrade_by_passwd.py
+Now, it checks if the target of binary being written and the
+configured target of running device are same.  This check can be
+skipped by -s option.  Please note that FST-01 and FST-01SZ are
+different target, as it's MHz is different.
+
+
 * Major changes in Gnuk 1.2.17
 
   Released 2021-02-25, by NIIBE Yutaka
diff --git a/src/configure b/src/configure
index d230c1b..ced885e 100755
--- a/src/configure
+++ b/src/configure
@@ -46,7 +46,7 @@ hid_card_change=no
 factory_reset=no
 ackbtn_support=yes
 flash_override=""
-kdf_do=optional
+kdf_do=${kdf_do:-optional}
 # For emulation
 prefix=/usr/local
 exec_prefix='${prefix}'
@@ -219,7 +219,7 @@ if test "$target" = "GNU_LINUX"; then
   emulation="yes"
   cross=""
   mcu="none"
-  kdf_do=required
+  kdf_do=${kdf_do:-required}
   def_emulation="-DGNU_LINUX_EMULATION"
   def_memory_size="-DMEMORY_SIZE=1024"
   enable_hexoutput=""