diff --git a/ChangeLog b/ChangeLog
index 0487c88..fbeb4c7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-14  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* VERSION: 1.15.
+	* doc/chopstx.texi (VERSION): 1.15.
+
 2019-05-13  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* board/board-maple-mini.h: Assert USB D+ pull-up.
diff --git a/NEWS b/NEWS
index 4dbcfa4..3a5d6ed 100644
--- a/NEWS
+++ b/NEWS
@@ -3,23 +3,24 @@ NEWS - Noteworthy changes
 
 * Major changes in Chopstx 1.15
 
-  Released 2019-05-1X
+  Released 2019-05-14
 
 ** SYS version 4.0
-USB initialization/finalization demarcation has been changed.
-Enabling/disabling USB module is done by USB driver.  SYS routines
-only handles USB cable config.  For all boards, USB driver doesn't use
-usb_lld_sys_init/usb_lld_sys_shutdown (those routines only makes sense
-for USB self powered situation, which Chopstx does not support yet).
+USB initialization/finalization API has been changed.  SYS routines
+only handle USB cable configuration when supported by a board.
 
 ** USB driver change
 Enabling/disabling USB module is done by USB driver.  It's
 responsibility of board configuration to enable external transistor
-for pull-up D+-line.
+for pull-up D+-line by board/*.h.  For all boards, USB driver doesn't
+use usb_lld_sys_init or usb_lld_sys_shutdown (those routines only can
+be used for USB self powered system, which Chopstx does not support
+yet).
 
 ** Board configuration change
 For USB driver change, board-maple-mini.h, board-olimex-stm32-h103.h,
-board-stbee.h, and board-stm32-primer2.h were changed.
+board-stbee.h, and board-stm32-primer2.h were changed.  Pull-up is
+enabled at the time of gpio_init.
 
 ** Cortex-M4 support
 Cortex-M4 support has been added.  Not supporting use of FPU or DSP,
@@ -31,6 +32,12 @@ USART and USB drivers are added.
 ** New board support: ST Nucleo-32 L432
 ST Nucleo-32 L432 is a small board with ST-Link/V2-1.
 
+** Minor implementation change: chopstx_claim_irq
+If the interrupt is disabled (possibly by chx_intr) when
+chopstx_claim_irq is called, INTR->ready is set to 1.  This allows
+calling chopstx_claim_irq after hardware initialization which may
+cause an interrupt before the call of chopstx_claim_irq.
+
 
 * Major changes in Chopstx 1.14
 
diff --git a/README b/README
index af873a2..77cbb43 100644
--- a/README
+++ b/README
@@ -1,6 +1,6 @@
 Chopstx - Threads and only Threads
-							 Version 2.0
-							  2018-0X-XX
+							Version 1.15
+							  2018-05-14
 							Niibe Yutaka
 					     Flying Stone Technology
 
diff --git a/VERSION b/VERSION
index 3cb3b85..fc2de1b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-release/1.14
+release/1.15
diff --git a/doc/chopstx.texi b/doc/chopstx.texi
index 614681f..ecd0ca5 100644
--- a/doc/chopstx.texi
+++ b/doc/chopstx.texi
@@ -1,7 +1,7 @@
 \input texinfo                      @c -*-texinfo-*-
 @c %**start of header
 @setfilename chopstx.info
-@set VERSION 1.14
+@set VERSION 1.15
 @settitle Chopstx Reference Manual
 @c Unify some of the indices.
 @syncodeindex tp fn
@@ -193,7 +193,7 @@ Running CPU clock in MHz.  Used for chopstx_usec_wait.
 @section Honourable poverty
 
 Chopstx is an effort against many features.  It encourages doing
-harder decision earlier.
+harder decision earlier (because of less features).
 
 Along with Moore's law, MCU implementations and their software are
 getting more complex.  It's been getting more flexibile, versatile,
@@ -220,9 +220,9 @@ In this situation, against existing practice, Chopstx is a challenge
 to handle all food by only two wooden sticks.  It's not fork and exec
 nor forks and knives.
 
-In Japan, it is common among families, to have each private chopsticks
-in home.  It's like these chopsticks are father's, these chopsticks
-are mother's... son's and daughter's.
+In Japan, it is common among families, to have private chopsticks for
+each individual at home.  It's like: these chopsticks are father's,
+these chopsticks are mother's... son's and daughter's.
 
 I hope Chopstx is the one for you.
 
@@ -262,8 +262,8 @@ implementation.  To cover all the cases, tests needed can become huge.
 A simple practice like following is good when it's enough: doing all
 initialization at start, then running threads to work.
 
-If possible, avoid supporting fine grain power control and/or dynamic
-clock frequency change.
+If possible, it's better to avoid supporting fine grain power control
+and/or dynamic clock frequency change.
 
 @c ********************************************