diff --git a/builddefs/build_vial.mk b/builddefs/build_vial.mk
index 1002e93b5d..48953c78a7 100644
--- a/builddefs/build_vial.mk
+++ b/builddefs/build_vial.mk
@@ -6,8 +6,10 @@ TAP_DANCE_ENABLE ?= yes
 ifeq ($(strip $(TAP_DANCE_ENABLE)), yes)
     OPT_DEFS += -DTAPPING_TERM_PER_KEY
 endif
+CAPS_WORD_ENABLE ?= yes
 COMBO_ENABLE ?= yes
 KEY_OVERRIDE_ENABLE ?= yes
+LAYER_LOCK_ENABLE ?= yes
 SRC += $(QUANTUM_DIR)/vial.c
 OPT_DEFS += -DVIAL_ENABLE -DNO_DEBUG -DSERIAL_NUMBER=\"vial:f64c2b3c\"
 
@@ -26,7 +28,7 @@ ifeq ($(strip $(QMK_SETTINGS)), yes)
     OPT_DEFS += -DQMK_SETTINGS \
         -DAUTO_SHIFT_NO_SETUP -DAUTO_SHIFT_REPEAT_PER_KEY -DAUTO_SHIFT_NO_AUTO_REPEAT_PER_KEY \
         -DPERMISSIVE_HOLD_PER_KEY -DHOLD_ON_OTHER_KEY_PRESS_PER_KEY -DQUICK_TAP_TERM_PER_KEY -DRETRO_TAPPING_PER_KEY \
-        -DCOMBO_TERM_PER_COMBO -DCHORDAL_HOLD -DFLOW_TAP_TERM=321
+        -DCOMBO_TERM_PER_COMBO -DCHORDAL_HOLD -DFLOW_TAP_TERM=321 -DCAPS_WORD_INVERT_ON_SHIFT
 endif
 
 # Generate Vial layout definition header from JSON
diff --git a/quantum/vial.c b/quantum/vial.c
index f5019bb5bf..c1ae54777e 100644
--- a/quantum/vial.c
+++ b/quantum/vial.c
@@ -224,6 +224,16 @@ void vial_handle_cmd(uint8_t *msg, uint8_t length) {
                 msg[0] = VIAL_TAP_DANCE_ENTRIES;
                 msg[1] = VIAL_COMBO_ENTRIES;
                 msg[2] = VIAL_KEY_OVERRIDE_ENTRIES;
+
+                // The last byte of msg indicates optionally supported features.
+                msg[length - 1] = (0
+#ifdef CAPS_WORD_ENABLE
+                        | (1 << 0)  // Bit 0: Caps Word.
+#endif
+#ifdef LAYER_LOCK_ENABLE
+                        | (1 << 1)  // Bit 1: Layer Lock.
+#endif
+                        );
                 break;
             }
 #ifdef VIAL_TAP_DANCE_ENABLE
diff --git a/quantum/vial_ensure_keycode.h b/quantum/vial_ensure_keycode.h
index 1c0dff2962..0f31036e4e 100644
--- a/quantum/vial_ensure_keycode.h
+++ b/quantum/vial_ensure_keycode.h
@@ -352,6 +352,7 @@ _Static_assert(MO(1) == 0x5221, "");
 _Static_assert(DF(1) == 0x5241, "");
 _Static_assert(TG(1) == 0x5261, "");
 _Static_assert(OSL(1) == 0x5281, "");
+_Static_assert(PDF(1) == 0x52E1, "");
 _Static_assert(LM(1, KC_A) == 0x5024, "");
 _Static_assert(OSM(MOD_RSFT) == 0x52B2, "");
 _Static_assert(TT(1) == 0x52C1, "");
@@ -810,9 +811,13 @@ _Static_assert(MI_BENDU == 0x718F, "");
 
 _Static_assert(RESET == 0x7C00, "");
 
+_Static_assert(QK_CAPS_WORD_TOGGLE == 0x7C73, "");
+
 _Static_assert(FN_MO13 == 0x7C77, "");
 _Static_assert(FN_MO23 == 0x7C78, "");
 
+_Static_assert(QK_LAYER_LOCK == 0x7C7B, "");
+
 /* Ensure that we have 64 USERxx keycodes */
 _Static_assert(QK_KB == 0x7E00, "");
 _Static_assert(QK_KB_MAX == 0x7E3F, "");