diff --git a/src/edit.c b/src/edit.c
index 2e6a980..01e5cc2 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -330,7 +330,7 @@
 
 	// Disable modifyOtherKeys, keys with modifiers would cause exiting
 	// Insert mode.
-	out_str(T_CTE);
+	out_str_t_TE();
     }
 
     /*
diff --git a/src/globals.h b/src/globals.h
index 9d70da6..a5e3982 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1377,6 +1377,24 @@
 // no longer be used.
 EXTERN int seenModifyOtherKeys INIT(= FALSE);
 
+// The state for the Kitty keyboard protocol.
+typedef enum {
+    // Initially we have no clue if the protocol is on or off.
+    KKPS_INITIAL,
+    // Used when receiving the state and the flags are zero.
+    KKPS_OFF,
+    // Used when receiving the state and the flags are non-zero.
+    KKPS_ENABLED,
+    // Used after outputting t_KE when the state was KKPS_ENABLED.  We do not
+    // really know if t_KE actually disabled the protocol, the following t_KI
+    // is expected to request the state, but the response may come only later.
+    KKPS_DISABLED,
+    // Used after outputting t_KE when the state was not KKPS_ENABLED.
+    KKPS_AFTER_T_KE,
+} kkpstate_T;
+
+EXTERN kkpstate_T kitty_protocol_state INIT(= KKPS_INITIAL);
+
 EXTERN int no_mapping INIT(= FALSE);	// currently no mapping allowed
 EXTERN int no_zero_mapping INIT(= 0);	// mapping zero not allowed
 EXTERN int allow_keys INIT(= FALSE);	// allow key codes when no_mapping
diff --git a/src/libvterm/include/vterm.h b/src/libvterm/include/vterm.h
index e5887c8..6a967db 100644
--- a/src/libvterm/include/vterm.h
+++ b/src/libvterm/include/vterm.h
@@ -368,6 +368,7 @@
 size_t vterm_output_read(VTerm *vt, char *buffer, size_t len);
 
 int vterm_is_modify_other_keys(VTerm *vt);
+int vterm_is_kitty_keyboard(VTerm *vt);
 void vterm_keyboard_unichar(VTerm *vt, uint32_t c, VTermModifier mod);
 void vterm_keyboard_key(VTerm *vt, VTermKey key, VTermModifier mod);
 
diff --git a/src/libvterm/src/keyboard.c b/src/libvterm/src/keyboard.c
index ffd8319..7a44670 100644
--- a/src/libvterm/src/keyboard.c
+++ b/src/libvterm/src/keyboard.c
@@ -10,6 +10,12 @@
   return vt->state->mode.modify_other_keys;
 }
 
+// VIM: added
+int vterm_is_kitty_keyboard(VTerm *vt)
+{
+  return vt->state->mode.kitty_keyboard;
+}
+
 
 void vterm_keyboard_unichar(VTerm *vt, uint32_t c, VTermModifier mod)
 {
@@ -19,6 +25,12 @@
     return;
   }
 
+  // VIM: added kitty keyboard protocol support
+  if (vterm_is_kitty_keyboard(vt) && mod != 0) {
+    vterm_push_output_sprintf_ctrl(vt, C1_CSI, "%d;%du", c, mod+1);
+    return;
+  }
+
   /* The shift modifier is never important for Unicode characters
    * apart from Space
    */
@@ -166,8 +178,10 @@
     break;
 
   case KEYCODE_TAB:
+    if (vterm_is_kitty_keyboard(vt) && mod != 0)
+      vterm_push_output_sprintf_ctrl(vt, C1_CSI, "9;%du", mod+1);
     /* Shift-Tab is CSI Z but plain Tab is 0x09 */
-    if(mod == VTERM_MOD_SHIFT)
+    else if(mod == VTERM_MOD_SHIFT)
       vterm_push_output_sprintf_ctrl(vt, C1_CSI, "Z");
     else if(mod & VTERM_MOD_SHIFT)
       vterm_push_output_sprintf_ctrl(vt, C1_CSI, "1;%dZ", mod+1);
@@ -186,7 +200,10 @@
   case KEYCODE_LITERAL: case_LITERAL:
     if (vterm_is_modify_other_keys(vt) && mod != 0)
       vterm_push_output_sprintf_ctrl(vt, C1_CSI, "27;%d;%d~", mod+1, k.literal);
-    else if(mod & (VTERM_MOD_SHIFT|VTERM_MOD_CTRL))
+    else if (vterm_is_kitty_keyboard(vt) && mod == 0 && k.literal == '\x1b')
+      vterm_push_output_sprintf_ctrl(vt, C1_CSI, "%du", k.literal);
+    else if ((vterm_is_kitty_keyboard(vt) && mod != 0)
+	|| (mod & (VTERM_MOD_SHIFT|VTERM_MOD_CTRL)))
       vterm_push_output_sprintf_ctrl(vt, C1_CSI, "%d;%du", k.literal, mod+1);
     else
       vterm_push_output_sprintf(vt, mod & VTERM_MOD_ALT ? ESC_S "%c" : "%c", k.literal);
diff --git a/src/libvterm/src/state.c b/src/libvterm/src/state.c
index 8aae7d1..33395e9 100644
--- a/src/libvterm/src/state.c
+++ b/src/libvterm/src/state.c
@@ -1423,9 +1423,37 @@
     }
     break;
 
-  case LEADER('>', 0x6d): // xterm resource modifyOtherKeys
+  case LEADER('>', 0x6d): // CSI > 4 ; Pv m   xterm resource modifyOtherKeys
     if (argcount == 2 && args[0] == 4)
+    {
+      // can't have both modify_other_keys and kitty_keyboard
+      state->mode.kitty_keyboard = 0;
+
       state->mode.modify_other_keys = args[1] == 2;
+    }
+    break;
+
+  case LEADER('>', 0x75): // CSI > 1 u  enable kitty keyboard protocol
+    if (argcount == 1 && args[0] == 1)
+    {
+      // can't have both modify_other_keys and kitty_keyboard
+      state->mode.modify_other_keys = 0;
+
+      state->mode.kitty_keyboard = 1;
+    }
+    break;
+
+  case LEADER('<', 0x75): // CSI < u  disable kitty keyboard protocol
+    if (argcount <= 1)
+      state->mode.kitty_keyboard = 0;
+    break;
+
+  case LEADER('?', 0x75): // CSI ? u  request kitty keyboard protocol state
+    if (argcount <= 1)
+      // TODO: this only uses the values zero and one.  The protocol specifies
+      // more values, the progressive enhancement flags.
+      vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?%du",
+						   state->mode.kitty_keyboard);
     break;
 
   case 0x6e: // DSR - ECMA-48 8.3.35
diff --git a/src/libvterm/src/vterm_internal.h b/src/libvterm/src/vterm_internal.h
index 0e389d0..3e95611 100644
--- a/src/libvterm/src/vterm_internal.h
+++ b/src/libvterm/src/vterm_internal.h
@@ -130,6 +130,7 @@
     unsigned int bracketpaste:1;
     unsigned int report_focus:1;
     unsigned int modify_other_keys:1;
+    unsigned int kitty_keyboard:1;
   } mode;
 
   VTermEncodingInstance encoding[4], encoding_utf8;
diff --git a/src/map.c b/src/map.c
index 4dec9e7..ee249c7 100644
--- a/src/map.c
+++ b/src/map.c
@@ -312,8 +312,27 @@
     // Prevent mappings to be cleared while at the more prompt.
     ++map_locked;
 
-    if (p_verbose > 0 && keyround == 1 && seenModifyOtherKeys)
-	msg_puts(_("Seen modifyOtherKeys: true"));
+    if (p_verbose > 0 && keyround == 1)
+    {
+	if (seenModifyOtherKeys)
+	    msg_puts(_("Seen modifyOtherKeys: true"));
+	if (kitty_protocol_state != KKPS_INITIAL)
+	{
+	    char *name = _("Unknown");
+	    switch (kitty_protocol_state)
+	    {
+		case KKPS_INITIAL: break;
+		case KKPS_OFF: name = _("Off"); break;
+		case KKPS_ENABLED: name = _("On"); break;
+		case KKPS_DISABLED: name = _("Disabled"); break;
+		case KKPS_AFTER_T_KE: name = _("Cleared"); break;
+	    }
+
+	    char buf[200];
+	    vim_snprintf(buf, sizeof(buf), _("Kitty keyboard protocol: %s"), name);
+	    msg_puts(buf);
+	}
+    }
 
     // need to loop over all global hash lists
     for (int hash = 0; hash < 256 && !got_int; ++hash)
diff --git a/src/normal.c b/src/normal.c
index 5000f53..938ae71 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -424,7 +424,7 @@
 	    // Disable bracketed paste and modifyOtherKeys here, we won't
 	    // recognize the escape sequences with 'esckeys' off.
 	    out_str(T_BD);
-	    out_str(T_CTE);
+	    out_str_t_TE();
 	}
 
 	*cp = plain_vgetc();
diff --git a/src/option.h b/src/option.h
index eed12e8..6f27013 100644
--- a/src/option.h
+++ b/src/option.h
@@ -698,6 +698,7 @@
 #endif
 EXTERN char_u	*p_kp;		// 'keywordprg'
 EXTERN char_u	*p_km;		// 'keymodel'
+EXTERN char_u	*p_kpc;		// 'keyprotocol'
 #ifdef FEAT_LANGMAP
 EXTERN char_u	*p_langmap;	// 'langmap'
 EXTERN int	p_lnr;		// 'langnoremap'
diff --git a/src/optiondefs.h b/src/optiondefs.h
index 5b3860b..0278b60 100644
--- a/src/optiondefs.h
+++ b/src/optiondefs.h
@@ -1447,6 +1447,10 @@
     {"keymodel",    "km",   P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
 			    (char_u *)&p_km, PV_NONE,
 			    {(char_u *)"", (char_u *)0L} SCTX_INIT},
+    {"keyprotocol", "kpc",  P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
+			    (char_u *)&p_kpc, PV_NONE,
+			    {(char_u *)"kitty:kitty,foot:kitty,wezterm:kitty,xterm:mok2", (char_u *)0L}
+			    SCTX_INIT},
     {"keywordprg",  "kp",   P_STRING|P_EXPAND|P_VI_DEF|P_SECURE,
 			    (char_u *)&p_kp, PV_KP,
 			    {
diff --git a/src/optionstr.c b/src/optionstr.c
index 9e9d18f..084b438 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -1663,6 +1663,13 @@
 	}
     }
 
+    // 'keyprotocol'
+    else if (varp == &p_kpc)
+    {
+	if (match_keyprotocol(NULL) == KEYPROTOCOL_FAIL)
+	    errmsg = e_invalid_argument;
+    }
+
     // 'mousemodel'
     else if (varp == &p_mousem)
     {
diff --git a/src/os_unix.c b/src/os_unix.c
index db57902..0540fc9 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5348,9 +5348,9 @@
 		long delay_msec = 1;
 
 		if (tmode == TMODE_RAW)
-		    // possibly disables modifyOtherKeys, so that the system
-		    // can recognize CTRL-C
-		    out_str(T_CTE);
+		    // Possibly disables modifyOtherKeys, so that the system
+		    // can recognize CTRL-C.
+		    out_str_t_TE();
 
 		/*
 		 * Similar to the loop above, but only handle X events, no
diff --git a/src/proto/term.pro b/src/proto/term.pro
index 7ce14b9..b1c691d 100644
--- a/src/proto/term.pro
+++ b/src/proto/term.pro
@@ -4,6 +4,7 @@
 void init_term_props(int all);
 void f_terminalprops(typval_T *argvars, typval_T *rettv);
 void set_color_count(int nr);
+keyprot_T match_keyprotocol(char_u *term);
 int set_termname(char_u *term);
 void free_cur_term(void);
 void getlinecol(long *cp, long *rp);
@@ -46,6 +47,7 @@
 void shell_resized(void);
 void shell_resized_check(void);
 void set_shellsize(int width, int height, int mustset);
+void out_str_t_TE(void);
 void settmode(tmode_T tmode);
 void starttermcap(void);
 void stoptermcap(void);
diff --git a/src/term.c b/src/term.c
index bb1e283..7f639dd 100644
--- a/src/term.c
+++ b/src/term.c
@@ -587,6 +587,32 @@
 };
 
 /*
+ * Additions for using modifyOtherKeys level 2.  Same as what is used for
+ * xterm.
+ */
+static tcap_entry_T builtin_mok2[] = {
+    {(int)KS_CTI,	"\033[>4;2m"},
+    {(int)KS_CTE,	"\033[>4;m"},
+
+    {(int)KS_NAME,	NULL}  // end marker
+};
+
+/*
+ * Additions for using the Kitty keyboard protocol.
+ */
+static tcap_entry_T builtin_kitty[] = {
+    // t_TI enables the kitty keyboard protocol, requests the kitty keyboard
+    // protocol state and requests the version response.
+    {(int)KS_CTI,	"\033[>1u\033[?u\033[>c"},
+
+    // t_TE also disabled modifyOtherKeys, because t_TI from xterm may already
+    // have been used.
+    {(int)KS_CTE,	"\033[>4;m\033[<u"},
+
+    {(int)KS_NAME,	NULL}  // end marker
+};
+
+/*
  * iris-ansi for Silicon Graphics machines.
  */
 static tcap_entry_T builtin_iris_ansi[] = {
@@ -1494,26 +1520,22 @@
 }
 
 /*
- * Parsing of the builtin termcap entries.
- * Caller should check if "term" is a valid builtin terminal name.
- * The terminal's name is not set, as this is already done in termcapinit().
+ * Apply entries from a builtin termcap.
  */
     static void
-parse_builtin_tcap(char_u *term)
+apply_builtin_tcap(char_u *term, tcap_entry_T *entries, int overwrite)
 {
-    tcap_entry_T *p = find_builtin_term(term);
-    if (p == NULL)  // builtin term not found
-	return;
-
     int term_8bit = term_is_8bit(term);
 
-    for ( ; p->bt_entry != (int)KS_NAME && p->bt_entry != BT_EXTRA_KEYS; ++p)
+    for (tcap_entry_T *p = entries;
+	      p->bt_entry != (int)KS_NAME && p->bt_entry != BT_EXTRA_KEYS; ++p)
     {
 	if ((int)p->bt_entry >= 0)	// KS_xx entry
 	{
-	    // Only set the value if it wasn't set yet.
+	    // Only set the value if it wasn't set yet or "overwrite" is TRUE.
 	    if (term_strings[p->bt_entry] == NULL
-				 || term_strings[p->bt_entry] == empty_option)
+		    || term_strings[p->bt_entry] == empty_option
+		    || overwrite)
 	    {
 #ifdef FEAT_EVAL
 		int opt_idx = -1;
@@ -1557,13 +1579,26 @@
 	    char_u  name[2];
 	    name[0] = KEY2TERMCAP0((int)p->bt_entry);
 	    name[1] = KEY2TERMCAP1((int)p->bt_entry);
-	    if (find_termcode(name) == NULL)
+	    if (find_termcode(name) == NULL || overwrite)
 		add_termcode(name, (char_u *)p->bt_string, term_8bit);
 	}
     }
 }
 
 /*
+ * Parsing of the builtin termcap entries.
+ * Caller should check if "term" is a valid builtin terminal name.
+ * The terminal's name is not set, as this is already done in termcapinit().
+ */
+    static void
+parse_builtin_tcap(char_u *term)
+{
+    tcap_entry_T *entries = find_builtin_term(term);
+    if (entries != NULL)
+	apply_builtin_tcap(term, entries, FALSE);
+}
+
+/*
  * Set number of colors.
  * Store it as a number in t_colors.
  * Store it as a string in T_CCO (using nr_colors[]).
@@ -1799,6 +1834,67 @@
 }
 
 /*
+ * Parse the 'keyprotocol' option, match against "term" and return the protocol
+ * for the first matching entry.
+ * When "term" is NULL then compile all patterns to check for any errors.
+ * Returns KEYPROTOCOL_FAIL if a pattern cannot be compiled.
+ * Returns KEYPROTOCOL_NONE if there is no match.
+ */
+    keyprot_T
+match_keyprotocol(char_u *term)
+{
+    int		len = (int)STRLEN(p_kpc) + 1;
+    char_u	*buf = alloc(len);
+    if (buf == NULL)
+	return KEYPROTOCOL_FAIL;
+
+    keyprot_T	ret = KEYPROTOCOL_FAIL;
+    char_u	*p = p_kpc;
+    while (*p != NUL)
+    {
+	// Isolate one comma separated item.
+	(void)copy_option_part(&p, buf, len, ",");
+	char_u *colon = vim_strchr(buf, ':');
+	if (colon == NULL || colon == buf || colon[1] == NUL)
+	    goto theend;
+	*colon = NUL;
+
+	keyprot_T prot;
+	if (STRCMP(colon + 1, "none") == 0)
+	    prot = KEYPROTOCOL_NONE;
+	else if (STRCMP(colon + 1, "mok2") == 0)
+	    prot = KEYPROTOCOL_MOK2;
+	else if (STRCMP(colon + 1, "kitty") == 0)
+	    prot = KEYPROTOCOL_KITTY;
+	else
+	    goto theend;
+
+	regmatch_T regmatch;
+	CLEAR_FIELD(regmatch);
+	regmatch.rm_ic = TRUE;
+	regmatch.regprog = vim_regcomp(buf, RE_MAGIC);
+	if (regmatch.regprog == NULL)
+	    goto theend;
+
+	int match = term != NULL && vim_regexec(&regmatch, term, (colnr_T)0);
+	vim_regfree(regmatch.regprog);
+	if (match)
+	{
+	    ret = prot;
+	    goto theend;
+	}
+
+    }
+
+    // No match found, use "none".
+    ret = KEYPROTOCOL_NONE;
+
+theend:
+    vim_free(buf);
+    return ret;
+}
+
+/*
  * Set terminal options for terminal "term".
  * Return OK if terminal 'term' was found in a termcap, FAIL otherwise.
  *
@@ -1924,6 +2020,15 @@
 	    }
 #endif
 	    parse_builtin_tcap(term);
+
+	    // Use the 'keyprotocol' option to adjust the t_TE and t_TI
+	    // termcap entries if there is an entry maching "term".
+	    keyprot_T kpc = match_keyprotocol(term);
+	    if (kpc == KEYPROTOCOL_KITTY)
+		apply_builtin_tcap(term, builtin_kitty, TRUE);
+	    else if (kpc == KEYPROTOCOL_MOK2)
+		apply_builtin_tcap(term, builtin_mok2, TRUE);
+
 #ifdef FEAT_GUI
 	    if (term_is_gui(term))
 	    {
@@ -3562,6 +3667,25 @@
 }
 
 /*
+ * Output T_CTE, the t_TE termcap entry, and handle expected effects.
+ * The code possibly disables modifyOtherKeys and the Kitty keyboard protocol.
+ */
+    void
+out_str_t_TE(void)
+{
+    out_str(T_CTE);
+
+    // When the kitty keyboard protocol is enabled we expect t_TE to disable
+    // it.  Remembering that it was detected to be enabled is useful in some
+    // situations.
+    if (kitty_protocol_state == KKPS_ENABLED
+	    || kitty_protocol_state == KKPS_DISABLED)
+	kitty_protocol_state = KKPS_DISABLED;
+    else
+	kitty_protocol_state = KKPS_AFTER_T_KE;
+}
+
+/*
  * Set the terminal to TMODE_RAW (for Normal mode) or TMODE_COOK (for external
  * commands and Ex mode).
  */
@@ -3613,7 +3737,7 @@
 		if (tmode != TMODE_RAW)
 		{
 		    out_str(T_BD);	// disable bracketed paste mode
-		    out_str(T_CTE);	// possibly disables modifyOtherKeys
+		    out_str_t_TE();	// possibly disables modifyOtherKeys
 		}
 		else
 		{
@@ -3714,7 +3838,8 @@
 	out_flush();
 	termcap_active = FALSE;
 	cursor_on();			// just in case it is still off
-	out_str(T_CTE);			// stop "raw" mode
+	out_str_t_TE();			// stop "raw" mode, modifyOtherKeys and
+					// Kitty keyboard protocol
 	out_str(T_TE);			// stop termcap mode
 	screen_start();			// don't know where cursor is now
 	out_flush();
@@ -5107,6 +5232,15 @@
 # endif
     }
 
+    // Kitty keyboard protocol status response: CSI ? flags u
+    else if (first == '?' && argc == 1 && trail == 'u')
+    {
+	// The protocol has various "progressive enhancement flags" values, but
+	// we only check for zero and non-zero here.
+	kitty_protocol_state = arg[0] == '0' ? KKPS_OFF : KKPS_ENABLED;
+	*slen = csi_len;
+    }
+
     // Check for a window position response from the terminal:
     //       {lead}3;{x};{y}t
     else if (did_request_winpos && argc == 3 && arg[0] == 3
diff --git a/src/terminal.c b/src/terminal.c
index 64e6ad4..fe82fa3 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -1587,6 +1587,13 @@
     if (modmask & (MOD_MASK_ALT | MOD_MASK_META))
 	mod |= VTERM_MOD_ALT;
 
+    // Ctrl-Shift-i may have the key "I" instead of "i", but for the kitty
+    // keyboard protocol should use "i".  Applies to all ascii letters.
+    if (ASCII_ISUPPER(c)
+	    && vterm_is_kitty_keyboard(curbuf->b_term->tl_vterm)
+	    && mod == (VTERM_MOD_CTRL | VTERM_MOD_SHIFT))
+	c = TOLOWER_ASC(c);
+
     /*
      * Convert special keys to vterm keys:
      * - Write keys to vterm: vterm_keyboard_key()
@@ -2182,6 +2189,19 @@
 
 static reduce_key_state_T  no_reduce_key_state = NRKS_NONE;
 
+/*
+ * Return TRUE if the term is using modifyOtherKeys level 2 or the kitty
+ * keyboard protocol.
+ */
+    static int
+vterm_using_key_protocol(void)
+{
+    return curbuf->b_term != NULL
+	&& curbuf->b_term->tl_vterm != NULL
+	&& (vterm_is_modify_other_keys(curbuf->b_term->tl_vterm)
+		|| vterm_is_kitty_keyboard(curbuf->b_term->tl_vterm));
+}
+
     void
 check_no_reduce_keys(void)
 {
@@ -2191,9 +2211,10 @@
 	    || curbuf->b_term->tl_vterm == NULL)
 	return;
 
-    if (vterm_is_modify_other_keys(curbuf->b_term->tl_vterm))
+    if (vterm_using_key_protocol())
     {
-	// "modify_other_keys" was enabled while waiting.
+	// "modify_other_keys" or kitty keyboard protocol was enabled while
+	// waiting.
 	no_reduce_key_state = NRKS_SET;
 	++no_reduce_keys;
     }
@@ -2216,8 +2237,7 @@
     ctrl_break_was_pressed = FALSE;
 #endif
 
-    if (curbuf->b_term->tl_vterm != NULL
-		       && vterm_is_modify_other_keys(curbuf->b_term->tl_vterm))
+    if (vterm_using_key_protocol())
     {
 	++no_reduce_keys;
 	no_reduce_key_state = NRKS_SET;
@@ -2641,12 +2661,13 @@
 
 /*
  * When modify_other_keys is set then do the reverse of raw_c_to_ctrl().
+ * Also when the Kitty keyboard protocol is used.
  * May set "mod_mask".
  */
     static int
 ctrl_to_raw_c(int c)
 {
-    if (c < 0x20 && vterm_is_modify_other_keys(curbuf->b_term->tl_vterm))
+    if (c < 0x20 && vterm_using_key_protocol())
     {
 	mod_mask |= MOD_MASK_CTRL;
 	return c + '@';
diff --git a/src/testdir/gen_opt_test.vim b/src/testdir/gen_opt_test.vim
index dd5f73e..7337217 100644
--- a/src/testdir/gen_opt_test.vim
+++ b/src/testdir/gen_opt_test.vim
@@ -113,6 +113,8 @@
       \ 'isprint': [['', '@', '@,48-52'], ['xxx', '@48']],
       \ 'keymap': [['', 'accents'], ['xxx']],
       \ 'keymodel': [['', 'startsel', 'startsel,stopsel'], ['xxx']],
+      \ 'keyprotocol': [['', 'xxx:none', 'yyy:mok2', 'zzz:kitty'],
+      \		[':none', 'xxx:', 'x:non', 'y:mok3', 'z:kittty']],
       \ 'langmap': [['', 'xX', 'aA,bB'], ['xxx']],
       \ 'lispoptions': [['', 'expr:0', 'expr:1'], ['xxx']],
       \ 'listchars': [['', 'eol:x', 'eol:x,space:y'], ['xxx']],
diff --git a/src/testdir/keycode_check.json b/src/testdir/keycode_check.json
index 868c2a9..218859f 100644
--- a/src/testdir/keycode_check.json
+++ b/src/testdir/keycode_check.json
@@ -1 +1 @@
-{"12xterm":{"Space":"20","version":"1b5b3e34313b3335363b3063","C-Tab":"1b5b32373b353b397e","A-Esc":"1b5b32373b333b32377e","C-Space":"1b5b32373b353b33327e","status":"","S-C-I":"1b5b32373b363b37337e","C-I":"1b5b32373b353b3130357e","S-Tab":"1b5b5a","Tab":"09","S-Space":"1b5b32373b323b33327e","A-Tab":"1b5b32373b333b397e","C-Esc":"1b5b32373b353b32377e","protocol":"mok2","A-Space":"1b5b32373b333b33327e","S-Esc":"1b","Esc":"1b"},"libvterm":{"Space":"20","version":"1b5b3e303b3130303b3063","C-Tab":"1b5b32373b353b397e","A-Esc":"1b5b32373b333b32377e","C-Space":"1b5b32373b353b33327e","status":"","S-C-I":"1b5b32373b363b37337e","C-I":"1b5b32373b353b3130357e","S-Tab":"1b5b5a","Tab":"09","resource":"","A-Tab":"1b5b32373b333b397e","S-Space":"1b5b32373b323b33327e","C-Esc":"1b5b32373b353b32377e","protocol":"mok2","A-Space":"1b5b32373b333b33327e","S-Esc":"1b","Esc":"1b"},"2kitty":{"Space":"20","version":"1b5b3e313b343030303b323163","C-Tab":"","A-Esc":"1b5b32373b313175","C-Space":"1b5b33323b3575","status":"1b5b3f3175","S-C-I":"1b5b3130353b3675","C-I":"1b5b3130353b3575","S-Tab":"1b5b393b3275","Tab":"09","S-Space":"20","A-Tab":"1b5b393b313175","C-Esc":"1b5b32373b3575","protocol":"kitty","A-Space":"1b5b33323b313175","S-Esc":"1b5b32373b3275","Esc":"1b5b323775"},"11xterm":{"Space":"20","version":"1b5b3e34313b3335363b3063","C-Tab":"09","A-Esc":"9b00","status":"","S-C-I":"09","C-I":"09","S-Tab":"1b5b5a","Tab":"09","S-Space":"20","A-Tab":"8900","C-Esc":"1b","protocol":"none","A-Space":"a000","S-Esc":"1b","Esc":"1b"}}
+{"31kitty":{"Space":"20","version":"1b5b3e313b343030303b323163","C-Tab":"","A-Esc":"1b5b32373b313175","C-Space":"1b5b33323b3575","status":"1b5b3f3175","S-C-I":"1b5b3130353b3675","C-I":"1b5b3130353b3575","S-Tab":"1b5b393b3275","Tab":"09","resource":"","A-Tab":"1b5b393b313175","S-Space":"20","C-Esc":"1b5b32373b3575","protocol":"kitty","A-Space":"1b5b33323b313175","S-Esc":"1b5b32373b3275","Esc":"1b5b323775"},"32libvterm":{"Space":"20","version":"1b5b3e303b3130303b3063","C-Tab":"1b5b393b3575","A-Esc":"1b5b32373b3375","C-Space":"1b5b33323b3575","status":"1b5b3f3175","S-C-I":"1b5b3130353b3675","C-I":"1b5b3130353b3575","S-Tab":"1b5b393b3275","Tab":"09","resource":"","A-Tab":"1b5b393b3375","S-Space":"1b5b33323b3275","C-Esc":"1b5b32373b3575","protocol":"kitty","A-Space":"1b5b33323b3375","S-Esc":"1b5b323775","Esc":"1b5b323775"},"22libvterm":{"Space":"20","version":"1b5b3e303b3130303b3063","C-Tab":"1b5b32373b353b397e","A-Esc":"1b5b32373b333b32377e","C-Space":"1b5b32373b353b33327e","status":"","S-C-I":"1b5b32373b363b37337e","C-I":"1b5b32373b353b3130357e","S-Tab":"1b5b5a","Tab":"09","resource":"","A-Tab":"1b5b32373b333b397e","S-Space":"1b5b32373b323b33327e","C-Esc":"1b5b32373b353b32377e","protocol":"mok2","A-Space":"1b5b32373b333b33327e","S-Esc":"1b","Esc":"1b"},"13kitty":{"Space":"20","version":"1b5b3e313b343030303b323163","C-Tab":"","A-Esc":"1b1b","status":"","S-C-I":"1b5b3130353b3675","C-I":"09","S-Tab":"1b5b5a","Tab":"09","resource":"","A-Tab":"1b09","S-Space":"20","C-Esc":"1b","protocol":"none","A-Space":"1b5b33323b313175","S-Esc":"1b","Esc":"1b"},"21xterm":{"Space":"20","version":"1b5b3e34313b3335363b3063","C-Tab":"1b5b32373b353b397e","A-Esc":"1b5b32373b333b32377e","C-Space":"1b5b32373b353b33327e","status":"","S-C-I":"1b5b32373b363b37337e","C-I":"1b5b32373b353b3130357e","S-Tab":"1b5b5a","Tab":"09","resource":"=30","A-Tab":"1b5b32373b333b397e","S-Space":"1b5b32373b323b33327e","C-Esc":"1b5b32373b353b32377e","protocol":"mok2","A-Space":"1b5b32373b333b33327e","S-Esc":"1b","Esc":"1b"},"12libvterm":{"Space":"20","version":"1b5b3e303b3130303b3063","C-Tab":"1b5b393b3575","A-Esc":"9b00","status":"","S-C-I":"1b5b5a","C-I":"09","S-Tab":"1b5b5a","Tab":"09","S-Space":"1b5b33323b3275","A-Tab":"8900","resource":"","C-Esc":"1b5b32373b3575","protocol":"none","A-Space":"a000","S-Esc":"1b","Esc":"1b"},"11xterm":{"Space":"20","version":"1b5b3e34313b3335363b3063","C-Tab":"09","A-Esc":"9b00","status":"","S-C-I":"09","C-I":"09","S-Tab":"1b5b5a","Tab":"09","S-Space":"20","A-Tab":"8900","C-Esc":"1b","protocol":"none","A-Space":"a000","S-Esc":"1b","Esc":"1b"}}
diff --git a/src/version.c b/src/version.c
index 42e7200..a96b11a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    930,
+/**/
     929,
 /**/
     928,
diff --git a/src/vim.h b/src/vim.h
index 14630e6..67751ff 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2257,6 +2257,14 @@
     ESTACK_SCRIPT,
 } estack_arg_T;
 
+// Return value of match_keyprotocol()
+typedef enum {
+    KEYPROTOCOL_NONE,
+    KEYPROTOCOL_MOK2,
+    KEYPROTOCOL_KITTY,
+    KEYPROTOCOL_FAIL
+} keyprot_T;
+
 // Flags for assignment functions.
 #define ASSIGN_VAR	0     // ":var" (nothing special)
 #define ASSIGN_FINAL	0x01  // ":final"