diff --git a/src/hb-ot-layout.hh b/src/hb-ot-layout.hh
index d73c5a3..b15d053 100644
--- a/src/hb-ot-layout.hh
+++ b/src/hb-ot-layout.hh
@@ -187,7 +187,7 @@
  * - General_Category: 5 bits.
  * - A bit each for:
  *   * Is it Default_Ignorable(); we have a modified Default_Ignorable().
- *   * Whether it's one of the three Mongolian Free Variation Selectors,
+ *   * Whether it's one of the four Mongolian Free Variation Selectors,
  *     CGJ, or other characters that are hidden but should not be ignored
  *     like most other Default_Ignorable()s do during matching.
  *   * Whether it's a grapheme continuation.
@@ -202,7 +202,7 @@
 enum hb_unicode_props_flags_t {
   UPROPS_MASK_GEN_CAT	= 0x001Fu,
   UPROPS_MASK_IGNORABLE	= 0x0020u,
-  UPROPS_MASK_HIDDEN	= 0x0040u, /* MONGOLIAN FREE VARIATION SELECTOR 1..3, or TAG characters */
+  UPROPS_MASK_HIDDEN	= 0x0040u, /* MONGOLIAN FREE VARIATION SELECTOR 1..4, or TAG characters */
   UPROPS_MASK_CONTINUATION=0x0080u,
 
   /* If GEN_CAT=FORMAT, top byte masks: */
diff --git a/src/hb-unicode.hh b/src/hb-unicode.hh
index ff6447b..4c28bb0 100644
--- a/src/hb-unicode.hh
+++ b/src/hb-unicode.hh
@@ -136,7 +136,7 @@
    * As such, we make exceptions for those four.
    * Also ignoring U+1BCA0..1BCA3. https://github.com/harfbuzz/harfbuzz/issues/503
    *
-   * Unicode 7.0:
+   * Unicode 14.0:
    * $ grep '; Default_Ignorable_Code_Point ' DerivedCoreProperties.txt | sed 's/;.*#/#/'
    * 00AD          # Cf       SOFT HYPHEN
    * 034F          # Mn       COMBINING GRAPHEME JOINER
@@ -145,6 +145,7 @@
    * 17B4..17B5    # Mn   [2] KHMER VOWEL INHERENT AQ..KHMER VOWEL INHERENT AA
    * 180B..180D    # Mn   [3] MONGOLIAN FREE VARIATION SELECTOR ONE..MONGOLIAN FREE VARIATION SELECTOR THREE
    * 180E          # Cf       MONGOLIAN VOWEL SEPARATOR
+   * 180F          # Mn       MONGOLIAN FREE VARIATION SELECTOR FOUR
    * 200B..200F    # Cf   [5] ZERO WIDTH SPACE..RIGHT-TO-LEFT MARK
    * 202A..202E    # Cf   [5] LEFT-TO-RIGHT EMBEDDING..RIGHT-TO-LEFT OVERRIDE
    * 2060..2064    # Cf   [5] WORD JOINER..INVISIBLE PLUS