diff --git a/include/X11/XF86keysym.h b/include/X11/XF86keysym.h
index bbac2b6..3d31aab 100644
--- a/include/X11/XF86keysym.h
+++ b/include/X11/XF86keysym.h
@@ -282,7 +282,7 @@
  * Where
  * - alignment by spaces
  * - the _EVDEVK macro must be used
- * - the hex code must be in uppercase hex
+ * - the hex code must be in lowercase hex
  * - the kernel version (kver) is in the form v5.10
  * - kver and key name are within a slash-star comment (a pipe is used in
  *   this example for technical reasons)
@@ -437,14 +437,14 @@
 #define XF86XK_ChannelUp                _EVDEVK(0x192)  /* v2.5.26 KEY_CHANNELUP */
 #define XF86XK_ChannelDown              _EVDEVK(0x193)  /* v2.5.26 KEY_CHANNELDOWN */
 /* TODO: unclear function               _EVDEVK(0x194)     v2.5.26 KEY_FIRST */
-/* TODO: unclear function               _EVDEVK(0x195)     v2.5.26 KEY_LAST */
+#define XF86XK_PriorChannel             _EVDEVK(0x195)  /* v2.5.26 KEY_LAST */
 /* TODO: unclear function               _EVDEVK(0x196)     v2.5.26 KEY_AB */
-/* TODO: unclear function               _EVDEVK(0x197)     v2.5.26 KEY_NEXT */
+#define XF86XK_ChapterNext              _EVDEVK(0x197)  /* v2.5.26 KEY_NEXT */
 /* TODO: unclear function               _EVDEVK(0x198)     v2.5.26 KEY_RESTART */
 #define XF86XK_MediaPlaySlow            _EVDEVK(0x199)  /* v2.5.26 KEY_SLOW */
 /* Use: XF86XK_AudioRandomPlay          _EVDEVK(0x19a)     v2.5.26 KEY_SHUFFLE */
 #define XF86XK_Break                    _EVDEVK(0x19b)  /* v2.5.26 KEY_BREAK */
-/* TODO: unclear function               _EVDEVK(0x19c)     v2.5.26 KEY_PREVIOUS */
+#define XF86XK_ChapterPrevious          _EVDEVK(0x19c)  /* v2.5.26 KEY_PREVIOUS */
 #define XF86XK_NumberEntryMode          _EVDEVK(0x19d)  /* v2.5.26 KEY_DIGITS */
 /* TODO: unclear function               _EVDEVK(0x19e)     v2.5.26 KEY_TEEN */
 /* TODO: unclear function (Twenties?)   _EVDEVK(0x19f)     v2.5.26 KEY_TWEN */