diff --git a/kotlin-native/runtime/src/main/kotlin/generated/_LetterChars.kt b/kotlin-native/runtime/src/main/kotlin/generated/_LetterChars.kt
index 5b54e6ed224..751f80ba42e 100644
--- a/kotlin-native/runtime/src/main/kotlin/generated/_LetterChars.kt
+++ b/kotlin-native/runtime/src/main/kotlin/generated/_LetterChars.kt
@@ -68,17 +68,17 @@ internal fun Char.isLetterImpl(): Boolean {
 }
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is a lower case letter, or it has contributory property Other_Lowercase.
  */
 internal fun Char.isLowerCaseImpl(): Boolean {
-    return getLetterType() == 1
+    return getLetterType() == 1 || code.isOtherLowercase()
 }
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is an upper case letter, or it has contributory property Other_Uppercase.
  */
 internal fun Char.isUpperCaseImpl(): Boolean {
-    return getLetterType() == 2
+    return getLetterType() == 2 || code.isOtherUppercase()
 }
 
 /**
diff --git a/kotlin-native/runtime/src/main/kotlin/generated/_OtherLowercaseChars.kt b/kotlin-native/runtime/src/main/kotlin/generated/_OtherLowercaseChars.kt
new file mode 100644
index 00000000000..d4beacb7154
--- /dev/null
+++ b/kotlin-native/runtime/src/main/kotlin/generated/_OtherLowercaseChars.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+@SharedImmutable
+private val otherLowerStart = intArrayOf(
+    0x00aa, 0x00ba, 0x02b0, 0x02c0, 0x02e0, 0x0345, 0x037a, 0x1d2c, 0x1d78, 0x1d9b, 0x2071, 0x207f, 0x2090, 0x2170, 0x24d0, 0x2c7c, 0xa69c, 0xa770, 0xa7f8, 0xab5c, 
+)
+@SharedImmutable
+private val otherLowerLength = intArrayOf(
+    1, 1, 9, 2, 5, 1, 1, 63, 1, 37, 1, 1, 13, 16, 26, 2, 2, 1, 2, 4, 
+)
+
+internal fun Int.isOtherLowercase(): Boolean {
+    val index = binarySearchRange(otherLowerStart, this)
+    return index >= 0 && this < otherLowerStart[index] + otherLowerLength[index]
+}
diff --git a/kotlin-native/runtime/src/main/kotlin/generated/_OtherUppercaseChars.kt b/kotlin-native/runtime/src/main/kotlin/generated/_OtherUppercaseChars.kt
new file mode 100644
index 00000000000..b5a4b08083b
--- /dev/null
+++ b/kotlin-native/runtime/src/main/kotlin/generated/_OtherUppercaseChars.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+internal fun Int.isOtherUppercase(): Boolean {
+    return this in 0x2160..0x216f
+            || this in 0x24b6..0x24cf
+            || this in 0x1f130..0x1f149
+            || this in 0x1f150..0x1f169
+            || this in 0x1f170..0x1f189
+}
diff --git a/kotlin-native/runtime/src/main/kotlin/generated/_StringLowercase.kt b/kotlin-native/runtime/src/main/kotlin/generated/_StringLowercase.kt
index a6b19050e37..2427fdde2e9 100644
--- a/kotlin-native/runtime/src/main/kotlin/generated/_StringLowercase.kt
+++ b/kotlin-native/runtime/src/main/kotlin/generated/_StringLowercase.kt
@@ -12,17 +12,13 @@ package kotlin.text
 
 @SharedImmutable
 private val casedStart = intArrayOf(
-    0x00aa, 0x00ba, 0x02b0, 0x02c0, 0x02e0, 0x0345, 0x037a, 0x1d2c, 0x1d78, 0x1d9b, 0x2071, 0x207f, 0x2090, 0x2160, 0x2170, 0x24b6, 0x24d0, 0x2c7c, 0xa69c, 0xa770, 
-    0xa7f8, 0xab5c, 0x10400, 0x104b0, 0x104d8, 0x10c80, 0x10cc0, 0x118a0, 0x16e40, 0x1d400, 0x1d456, 0x1d49e, 0x1d4a2, 0x1d4a5, 0x1d4a9, 0x1d4ae, 0x1d4bb, 0x1d4bd, 0x1d4c5, 0x1d507, 
-    0x1d50d, 0x1d516, 0x1d51e, 0x1d53b, 0x1d540, 0x1d546, 0x1d54a, 0x1d552, 0x1d6a8, 0x1d6c2, 0x1d6dc, 0x1d6fc, 0x1d716, 0x1d736, 0x1d750, 0x1d770, 0x1d78a, 0x1d7aa, 0x1d7c4, 0x1e900, 
-    0x1f130, 0x1f150, 0x1f170, 
+    0x10400, 0x104b0, 0x104d8, 0x10c80, 0x10cc0, 0x118a0, 0x16e40, 0x1d400, 0x1d456, 0x1d49e, 0x1d4a2, 0x1d4a5, 0x1d4a9, 0x1d4ae, 0x1d4bb, 0x1d4bd, 0x1d4c5, 0x1d507, 0x1d50d, 0x1d516, 
+    0x1d51e, 0x1d53b, 0x1d540, 0x1d546, 0x1d54a, 0x1d552, 0x1d6a8, 0x1d6c2, 0x1d6dc, 0x1d6fc, 0x1d716, 0x1d736, 0x1d750, 0x1d770, 0x1d78a, 0x1d7aa, 0x1d7c4, 0x1e900, 
 )
 @SharedImmutable
 private val casedEnd = intArrayOf(
-    0x00aa, 0x00ba, 0x02b8, 0x02c1, 0x02e4, 0x0345, 0x037a, 0x1d6a, 0x1d78, 0x1dbf, 0x2071, 0x207f, 0x209c, 0x216f, 0x217f, 0x24cf, 0x24e9, 0x2c7d, 0xa69d, 0xa770, 
-    0xa7f9, 0xab5f, 0x1044f, 0x104d3, 0x104fb, 0x10cb2, 0x10cf2, 0x118df, 0x16e7f, 0x1d454, 0x1d49c, 0x1d49f, 0x1d4a2, 0x1d4a6, 0x1d4ac, 0x1d4b9, 0x1d4bb, 0x1d4c3, 0x1d505, 0x1d50a, 
-    0x1d514, 0x1d51c, 0x1d539, 0x1d53e, 0x1d544, 0x1d546, 0x1d550, 0x1d6a5, 0x1d6c0, 0x1d6da, 0x1d6fa, 0x1d714, 0x1d734, 0x1d74e, 0x1d76e, 0x1d788, 0x1d7a8, 0x1d7c2, 0x1d7cb, 0x1e943, 
-    0x1f149, 0x1f169, 0x1f189, 
+    0x1044f, 0x104d3, 0x104fb, 0x10cb2, 0x10cf2, 0x118df, 0x16e7f, 0x1d454, 0x1d49c, 0x1d49f, 0x1d4a2, 0x1d4a6, 0x1d4ac, 0x1d4b9, 0x1d4bb, 0x1d4c3, 0x1d505, 0x1d50a, 0x1d514, 0x1d51c, 
+    0x1d539, 0x1d53e, 0x1d544, 0x1d546, 0x1d550, 0x1d6a5, 0x1d6c0, 0x1d6da, 0x1d6fa, 0x1d714, 0x1d734, 0x1d74e, 0x1d76e, 0x1d788, 0x1d7a8, 0x1d7c2, 0x1d7cb, 0x1e943, 
 )
 
 // Lu + Ll + Lt + Other_Lowercase + Other_Uppercase (PropList.txt of Unicode Character Database files)
@@ -35,6 +31,9 @@ internal fun Int.isCased(): Boolean {
             CharCategory.TITLECASE_LETTER.value -> return true
         }
     }
+    if (isOtherUppercase() || isOtherLowercase()) {
+        return true
+    }
     val index = binarySearchRange(casedStart, this)
     return index >= 0 && this <= casedEnd[index]
 }
diff --git a/kotlin-native/runtime/src/main/kotlin/kotlin/text/Char.kt b/kotlin-native/runtime/src/main/kotlin/kotlin/text/Char.kt
index b671caa9d58..e1ccb919336 100644
--- a/kotlin-native/runtime/src/main/kotlin/kotlin/text/Char.kt
+++ b/kotlin-native/runtime/src/main/kotlin/kotlin/text/Char.kt
@@ -101,9 +101,10 @@ external public actual fun Char.isISOControl(): Boolean
 public actual fun Char.isWhitespace(): Boolean = isWhitespaceImpl()
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is upper case.
  *
- * A character is considered to be an upper case letter if its [category] is [CharCategory.UPPERCASE_LETTER].
+ * A character is considered to be an upper case character if its [category] is [CharCategory.UPPERCASE_LETTER],
+ * or it has contributory property Other_Uppercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isUpperCase
  */
@@ -118,9 +119,10 @@ public actual fun Char.isUpperCase(): Boolean {
 }
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is lower case.
  *
- * A character is considered to be a lower case letter if its [category] is [CharCategory.LOWERCASE_LETTER].
+ * A character is considered to be a lower case character if its [category] is [CharCategory.LOWERCASE_LETTER],
+ * or it has contributory property Other_Lowercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isLowerCase
  */
diff --git a/libraries/stdlib/js-ir/src/generated/_LetterChars.kt b/libraries/stdlib/js-ir/src/generated/_LetterChars.kt
index 6fa6dd97d75..1fc593c5ec8 100644
--- a/libraries/stdlib/js-ir/src/generated/_LetterChars.kt
+++ b/libraries/stdlib/js-ir/src/generated/_LetterChars.kt
@@ -51,17 +51,17 @@ internal fun Char.isLetterImpl(): Boolean {
 }
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is a lower case letter, or it has contributory property Other_Lowercase.
  */
 internal fun Char.isLowerCaseImpl(): Boolean {
-    return getLetterType() == 1
+    return getLetterType() == 1 || code.isOtherLowercase()
 }
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is an upper case letter, or it has contributory property Other_Uppercase.
  */
 internal fun Char.isUpperCaseImpl(): Boolean {
-    return getLetterType() == 2
+    return getLetterType() == 2 || code.isOtherUppercase()
 }
 
 /**
diff --git a/libraries/stdlib/js-ir/src/generated/_OtherLowercaseChars.kt b/libraries/stdlib/js-ir/src/generated/_OtherLowercaseChars.kt
new file mode 100644
index 00000000000..08cddc0315f
--- /dev/null
+++ b/libraries/stdlib/js-ir/src/generated/_OtherLowercaseChars.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+private object OtherLowercase {
+    internal val otherLowerStart = intArrayOf(
+        0x00aa, 0x00ba, 0x02b0, 0x02c0, 0x02e0, 0x0345, 0x037a, 0x1d2c, 0x1d78, 0x1d9b, 0x2071, 0x207f, 0x2090, 0x2170, 0x24d0, 0x2c7c, 0xa69c, 0xa770, 0xa7f8, 0xab5c, 
+    )
+    internal val otherLowerLength = intArrayOf(
+        1, 1, 9, 2, 5, 1, 1, 63, 1, 37, 1, 1, 13, 16, 26, 2, 2, 1, 2, 4, 
+    )
+}
+
+internal fun Int.isOtherLowercase(): Boolean {
+    val index = binarySearchRange(OtherLowercase.otherLowerStart, this)
+    return index >= 0 && this < OtherLowercase.otherLowerStart[index] + OtherLowercase.otherLowerLength[index]
+}
diff --git a/libraries/stdlib/js-ir/src/generated/_OtherUppercaseChars.kt b/libraries/stdlib/js-ir/src/generated/_OtherUppercaseChars.kt
new file mode 100644
index 00000000000..d26518cb207
--- /dev/null
+++ b/libraries/stdlib/js-ir/src/generated/_OtherUppercaseChars.kt
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+internal fun Int.isOtherUppercase(): Boolean {
+    return this in 0x2160..0x216f
+            || this in 0x24b6..0x24cf
+}
diff --git a/libraries/stdlib/js/src/generated/_LetterChars.kt b/libraries/stdlib/js/src/generated/_LetterChars.kt
index 6fa6dd97d75..1fc593c5ec8 100644
--- a/libraries/stdlib/js/src/generated/_LetterChars.kt
+++ b/libraries/stdlib/js/src/generated/_LetterChars.kt
@@ -51,17 +51,17 @@ internal fun Char.isLetterImpl(): Boolean {
 }
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is a lower case letter, or it has contributory property Other_Lowercase.
  */
 internal fun Char.isLowerCaseImpl(): Boolean {
-    return getLetterType() == 1
+    return getLetterType() == 1 || code.isOtherLowercase()
 }
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is an upper case letter, or it has contributory property Other_Uppercase.
  */
 internal fun Char.isUpperCaseImpl(): Boolean {
-    return getLetterType() == 2
+    return getLetterType() == 2 || code.isOtherUppercase()
 }
 
 /**
diff --git a/libraries/stdlib/js/src/generated/_OtherLowercaseChars.kt b/libraries/stdlib/js/src/generated/_OtherLowercaseChars.kt
new file mode 100644
index 00000000000..08cddc0315f
--- /dev/null
+++ b/libraries/stdlib/js/src/generated/_OtherLowercaseChars.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+private object OtherLowercase {
+    internal val otherLowerStart = intArrayOf(
+        0x00aa, 0x00ba, 0x02b0, 0x02c0, 0x02e0, 0x0345, 0x037a, 0x1d2c, 0x1d78, 0x1d9b, 0x2071, 0x207f, 0x2090, 0x2170, 0x24d0, 0x2c7c, 0xa69c, 0xa770, 0xa7f8, 0xab5c, 
+    )
+    internal val otherLowerLength = intArrayOf(
+        1, 1, 9, 2, 5, 1, 1, 63, 1, 37, 1, 1, 13, 16, 26, 2, 2, 1, 2, 4, 
+    )
+}
+
+internal fun Int.isOtherLowercase(): Boolean {
+    val index = binarySearchRange(OtherLowercase.otherLowerStart, this)
+    return index >= 0 && this < OtherLowercase.otherLowerStart[index] + OtherLowercase.otherLowerLength[index]
+}
diff --git a/libraries/stdlib/js/src/generated/_OtherUppercaseChars.kt b/libraries/stdlib/js/src/generated/_OtherUppercaseChars.kt
new file mode 100644
index 00000000000..d26518cb207
--- /dev/null
+++ b/libraries/stdlib/js/src/generated/_OtherUppercaseChars.kt
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.text
+
+//
+// NOTE: THIS FILE IS AUTO-GENERATED by the GenerateUnicodeData.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+internal fun Int.isOtherUppercase(): Boolean {
+    return this in 0x2160..0x216f
+            || this in 0x24b6..0x24cf
+}
diff --git a/libraries/stdlib/js/src/kotlin/text/char.kt b/libraries/stdlib/js/src/kotlin/text/char.kt
index 59c027ea384..a9a3fd5b7c9 100644
--- a/libraries/stdlib/js/src/kotlin/text/char.kt
+++ b/libraries/stdlib/js/src/kotlin/text/char.kt
@@ -181,9 +181,10 @@ public actual fun Char.isDigit(): Boolean {
 }
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is upper case.
  *
- * A character is considered to be an upper case letter if its [category] is [CharCategory.UPPERCASE_LETTER].
+ * A character is considered to be an upper case character if its [category] is [CharCategory.UPPERCASE_LETTER],
+ * or it has contributory property Other_Uppercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isUpperCase
  */
@@ -199,9 +200,10 @@ public actual fun Char.isUpperCase(): Boolean {
 }
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is lower case.
  *
- * A character is considered to be a lower case letter if its [category] is [CharCategory.LOWERCASE_LETTER].
+ * A character is considered to be a lower case character if its [category] is [CharCategory.LOWERCASE_LETTER],
+ * or it has contributory property Other_Lowercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isLowerCase
  */
diff --git a/libraries/stdlib/jvm/src/kotlin/text/CharJVM.kt b/libraries/stdlib/jvm/src/kotlin/text/CharJVM.kt
index c57ab7623d8..bb54173f3f7 100644
--- a/libraries/stdlib/jvm/src/kotlin/text/CharJVM.kt
+++ b/libraries/stdlib/jvm/src/kotlin/text/CharJVM.kt
@@ -100,7 +100,8 @@ public actual fun Char.isWhitespace(): Boolean = Character.isWhitespace(this) ||
 /**
  * Returns `true` if this character is upper case.
  *
- * @see Character.isUpperCase
+ * A character is considered to be an upper case character if its [category] is [CharCategory.UPPERCASE_LETTER],
+ * or it has contributory property Other_Uppercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isUpperCase
  */
@@ -110,7 +111,8 @@ public actual inline fun Char.isUpperCase(): Boolean = Character.isUpperCase(thi
 /**
  * Returns `true` if this character is lower case.
  *
- * @see Character.isLowerCase
+ * A character is considered to be a lower case character if its [category] is [CharCategory.LOWERCASE_LETTER],
+ * or it has contributory property Other_Lowercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isLowerCase
  */
diff --git a/libraries/stdlib/src/kotlin/text/Char.kt b/libraries/stdlib/src/kotlin/text/Char.kt
index 86befea97d6..433a66e4080 100644
--- a/libraries/stdlib/src/kotlin/text/Char.kt
+++ b/libraries/stdlib/src/kotlin/text/Char.kt
@@ -296,9 +296,10 @@ public expect fun Char.isLetterOrDigit(): Boolean
 public expect fun Char.isDigit(): Boolean
 
 /**
- * Returns `true` if this character is an upper case letter.
+ * Returns `true` if this character is upper case.
  *
- * A character is considered to be an upper case letter if its [category] is [CharCategory.UPPERCASE_LETTER].
+ * A character is considered to be an upper case character if its [category] is [CharCategory.UPPERCASE_LETTER],
+ * or it has contributory property Other_Uppercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isUpperCase
  */
@@ -306,9 +307,10 @@ public expect fun Char.isDigit(): Boolean
 public expect fun Char.isUpperCase(): Boolean
 
 /**
- * Returns `true` if this character is a lower case letter.
+ * Returns `true` if this character is lower case.
  *
- * A character is considered to be a lower case letter if its [category] is [CharCategory.LOWERCASE_LETTER].
+ * A character is considered to be a lower case character if its [category] is [CharCategory.LOWERCASE_LETTER],
+ * or it has contributory property Other_Lowercase as defined by the Unicode Standard.
  *
  * @sample samples.text.Chars.isLowerCase
  */
diff --git a/libraries/stdlib/test/text/CharTest.kt b/libraries/stdlib/test/text/CharTest.kt
index 1c485ef6ac5..9b41396a06c 100644
--- a/libraries/stdlib/test/text/CharTest.kt
+++ b/libraries/stdlib/test/text/CharTest.kt
@@ -5,6 +5,7 @@
 
 package test.text
 
+import test.testOnNonJvm6And7
 import kotlin.test.*
 
 class CharTest {
@@ -521,4 +522,34 @@ class CharTest {
 
         assertEquals("\uFFFF", '\uFFFF'.titlecase())
     }
+
+    @Test
+    fun otherLowercaseProperty() {
+        testOnNonJvm6And7 {
+            val feminineOrdinalIndicator = '\u00AA'
+            assertTrue(feminineOrdinalIndicator.isLowerCase())
+            assertTrue(feminineOrdinalIndicator.isLetter())
+            assertFalse(feminineOrdinalIndicator.isUpperCase())
+
+            val circledLatinSmallLetterA = '\u24D0'
+            assertTrue(circledLatinSmallLetterA.isLowerCase())
+            assertFalse(circledLatinSmallLetterA.isLetter())
+            assertFalse(circledLatinSmallLetterA.isUpperCase())
+        }
+    }
+
+    @Test
+    fun otherUppercaseProperty() {
+        testOnNonJvm6And7 {
+            val romanNumberOne = '\u2160'
+            assertTrue(romanNumberOne.isUpperCase())
+            assertFalse(romanNumberOne.isLetter())
+            assertFalse(romanNumberOne.isLowerCase())
+
+            val circledLatinCapitalLetterZ = '\u24CF'
+            assertTrue(circledLatinCapitalLetterZ.isUpperCase())
+            assertFalse(circledLatinCapitalLetterZ.isLetter())
+            assertFalse(circledLatinCapitalLetterZ.isLowerCase())
+        }
+    }
 }
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/FileWriterUtils.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/FileWriterUtils.kt
index f8d1bcca978..6429e9bce20 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/FileWriterUtils.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/FileWriterUtils.kt
@@ -19,8 +19,9 @@ internal fun FileWriter.writeHeader(file: File, pkg: String) {
     appendLine(autoGeneratedWarning("GenerateUnicodeData.kt"))
 }
 
-internal fun FileWriter.writeIntArray(name: String, elements: List<Int>, strategy: RangesWritingStrategy) {
-    writeCollection(name, "intArrayOf", elements.map { it.toHexIntLiteral() }, strategy)
+internal fun FileWriter.writeIntArray(name: String, elements: List<Int>, strategy: RangesWritingStrategy, useHex: Boolean = true) {
+    val toString = if (useHex) Int::toHexIntLiteral else Int::toString
+    writeCollection(name, "intArrayOf", elements.map(toString), strategy)
 }
 
 private fun FileWriter.writeCollection(
@@ -98,3 +99,16 @@ internal fun String.hexToInt(): Int {
 internal fun List<String>.hexCharsToStringLiteral(): String {
     return "\"${joinToString(separator = "") { "\\u$it" }}\""
 }
+
+internal fun IntRange.rangeCheck(ch: String, indent: String): String {
+    val firstHex = first.toHexIntLiteral()
+    val lastHex = last.toHexIntLiteral()
+    return when (first) {
+        last ->
+            "$ch == $firstHex"
+        last - 1 ->
+            "$ch == $firstHex\n$indent|| $ch == $lastHex"
+        else ->
+            "$ch in $firstHex..$lastHex"
+    }
+}
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/GenerateUnicodeData.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/GenerateUnicodeData.kt
index f90b919765a..2af9f68ce87 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/GenerateUnicodeData.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/GenerateUnicodeData.kt
@@ -12,6 +12,8 @@ import generators.unicode.ranges.RangesGenerator
 import generators.unicode.mappings.string.StringCasingTestGenerator
 import generators.unicode.mappings.string.StringLowercaseGenerator
 import generators.unicode.mappings.string.StringUppercaseGenerator
+import generators.unicode.ranges.OtherLowercaseRangesGenerator
+import generators.unicode.ranges.OtherUppercaseRangesGenerator
 import templates.COPYRIGHT_NOTICE
 import templates.KotlinTarget
 import templates.readCopyrightNoticeFromProfile
@@ -61,6 +63,8 @@ fun main(args: Array<String>) {
     }
 
     val categoryRangesGenerators = mutableListOf<RangesGenerator>()
+    val otherLowercaseGenerators = mutableListOf<OtherLowercaseRangesGenerator>()
+    val otherUppercaseGenerators = mutableListOf<OtherUppercaseRangesGenerator>()
 
     fun addRangesGenerators(generatedDir: File, target: KotlinTarget) {
         val category = RangesGenerator.forCharCategory(generatedDir.resolve("_CharCategories.kt"), target)
@@ -71,6 +75,9 @@ fun main(args: Array<String>) {
         categoryRangesGenerators.add(digit)
         categoryRangesGenerators.add(letter)
         categoryRangesGenerators.add(whitespace)
+
+        otherLowercaseGenerators.add(OtherLowercaseRangesGenerator(generatedDir.resolve("_OtherLowercaseChars.kt"), target))
+        otherUppercaseGenerators.add(OtherUppercaseRangesGenerator(generatedDir.resolve("_OtherUppercaseChars.kt"), target))
     }
 
     val oneToOneMappingsGenerators = mutableListOf<MappingsGenerator>()
@@ -154,9 +161,18 @@ fun main(args: Array<String>) {
         bmpUnicodeDataLines.forEach { line -> it.appendLine(line) }
         it.generate()
     }
+    otherLowercaseGenerators.forEach {
+        propListLines.forEach { line -> it.appendLine(line) }
+        it.generate()
+    }
+    otherUppercaseGenerators.forEach {
+        propListLines.forEach { line -> it.appendLine(line) }
+        it.generate()
+    }
 
     categoryTestGenerator.let {
         bmpUnicodeDataLines.forEach { line -> it.appendLine(line) }
+        propListLines.forEach { line -> it.appendPropertyLine(line) }
         it.generate()
     }
 
@@ -176,7 +192,6 @@ fun main(args: Array<String>) {
     }
     stringLowercaseGenerator.let {
         specialCasingLines.forEach { line -> it.appendSpecialCasingLine(line) }
-        propListLines.forEach { line -> it.appendPropListLine(line) }
         wordBreakPropertyLines.forEach { line -> it.appendWordBreakPropertyLine(line) }
         it.generate()
     }
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/PropertyLine.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/PropertyLine.kt
index 83818dd5e7d..536dc431d1b 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/PropertyLine.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/PropertyLine.kt
@@ -14,6 +14,14 @@ internal class PropertyLine(properties: List<String>) {
     val rangeEnd: String = properties[0].split("..").last()
     val property: String = properties[1].takeWhile { it != ' ' }
 
+    fun intRange(): IntRange {
+        return rangeStart.hexToInt()..rangeEnd.hexToInt()
+    }
+
+    fun hexIntRangeLiteral(): String {
+        return "${rangeStart.hexToInt().toHexIntLiteral()}..${rangeEnd.hexToInt().toHexIntLiteral()}"
+    }
+
     override fun toString(): String {
         return "PropertyLine{rangeStart=$rangeStart" +
                 ", rangeEnd=$rangeEnd" +
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringCasingTestGenerator.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringCasingTestGenerator.kt
index 2c1c2fa18ad..a359ed49ed9 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringCasingTestGenerator.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringCasingTestGenerator.kt
@@ -57,9 +57,7 @@ internal class StringCasingTestGenerator(private val outputDir: File) {
             writer.appendLine("@SharedImmutable")
             writer.appendLine("private val $rangesArrayName = arrayOf<IntRange>(")
             ranges.forEach {
-                val start = it.rangeStart.hexToInt().toHexIntLiteral()
-                val end = it.rangeEnd.hexToInt().toHexIntLiteral()
-                writer.appendLine("    $start..$end,")
+                writer.appendLine("    ${it.hexIntRangeLiteral()},")
             }
             writer.appendLine(")")
             writer.appendLine()
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringLowercaseGenerator.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringLowercaseGenerator.kt
index 435871c2783..853c7670d40 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringLowercaseGenerator.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/mappings/string/StringLowercaseGenerator.kt
@@ -44,18 +44,11 @@ internal class StringLowercaseGenerator(
 
     override fun UnicodeDataLine.mapping(): String = lowercaseMapping
 
-    fun appendPropListLine(line: PropertyLine) {
-        when (line.property) {
-            "Other_Lowercase",
-            "Other_Uppercase" -> casedRanges.add(line.rangeStart.hexToInt()..line.rangeEnd.hexToInt())
-        }
-    }
-
     fun appendWordBreakPropertyLine(line: PropertyLine) {
         when (line.property) {
             "MidLetter",
             "MidNumLet",
-            "Single_Quote" -> caseIgnorableRanges.add(line.rangeStart.hexToInt()..line.rangeEnd.hexToInt())
+            "Single_Quote" -> caseIgnorableRanges.add(line.intRange())
         }
     }
 
@@ -101,6 +94,9 @@ internal class StringLowercaseGenerator(
                     CharCategory.TITLECASE_LETTER.value -> return true
                 }
             }
+            if (isOtherUppercase() || isOtherLowercase()) {
+                return true
+            }
             val index = binarySearchRange(casedStart, this)
             return index >= 0 && this <= casedEnd[index]
         }
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/CharCategoryTestGenerator.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/CharCategoryTestGenerator.kt
index 8c6b71c9cd4..61efbd83b62 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/CharCategoryTestGenerator.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/CharCategoryTestGenerator.kt
@@ -5,6 +5,7 @@
 
 package generators.unicode.ranges
 
+import generators.unicode.PropertyLine
 import generators.unicode.UnicodeDataLine
 import generators.unicode.writeHeader
 import java.io.File
@@ -38,6 +39,16 @@ internal class CharCategoryTestGenerator(private val outputFile: File) {
         }
     }
 
+    private val otherLowercaseRanges = mutableListOf<PropertyLine>()
+    private val otherUppercaseRanges = mutableListOf<PropertyLine>()
+
+    fun appendPropertyLine(line: PropertyLine) {
+        when (line.property) {
+            "Other_Lowercase" -> otherLowercaseRanges.add(line)
+            "Other_Uppercase" -> otherUppercaseRanges.add(line)
+        }
+    }
+
     fun generate() {
         writer?.appendLine(")")
         writer?.close()
@@ -111,10 +122,10 @@ class CharCategoryTest {
             val expectedIsLetterOrDigit = expectedIsLetter || expectedIsDigit
             test(expectedIsLetterOrDigit, char.isLetterOrDigit(), "isLetterOrDigit()")
             
-            val expectedIsLowerCase = isLowerCase(expectedCategoryCode)
+            val expectedIsLowerCase = isLowerCase(char, expectedCategoryCode)
             test(expectedIsLowerCase, char.isLowerCase(), "isLowerCase()")
 
-            val expectedIsUpperCase = isUpperCase(expectedCategoryCode)
+            val expectedIsUpperCase = isUpperCase(char, expectedCategoryCode)
             test(expectedIsUpperCase, char.isUpperCase(), "isUpperCase()")
 
             val expectedIsWhitespace = isWhitespace(char, expectedCategoryCode)
@@ -136,12 +147,20 @@ class CharCategoryTest {
         ).map { it.code }
     }
 
-    private fun isLowerCase(categoryCode: String): Boolean {
-        return categoryCode == CharCategory.LOWERCASE_LETTER.code
+    private val otherLowerChars = listOf<IntRange>(
+        ${otherLowercaseRanges.joinToString { it.hexIntRangeLiteral() }}
+    ).flatten().toHashSet()
+
+    private fun isLowerCase(char: Char, categoryCode: String): Boolean {
+        return categoryCode == CharCategory.LOWERCASE_LETTER.code || otherLowerChars.contains(char.code)
     }
 
-    private fun isUpperCase(categoryCode: String): Boolean {
-        return categoryCode == CharCategory.UPPERCASE_LETTER.code
+    private val otherUpperChars = listOf<IntRange>(
+        ${otherUppercaseRanges.joinToString { it.hexIntRangeLiteral() }}
+    ).flatten().toHashSet()
+
+    private fun isUpperCase(char: Char, categoryCode: String): Boolean {
+        return categoryCode == CharCategory.UPPERCASE_LETTER.code || otherUpperChars.contains(char.code)
     }
 
     private fun isWhitespace(char: Char, categoryCode: String): Boolean {
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherLowercaseRangesGenerator.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherLowercaseRangesGenerator.kt
new file mode 100644
index 00000000000..e5c0b500da3
--- /dev/null
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherLowercaseRangesGenerator.kt
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package generators.unicode.ranges
+
+import generators.unicode.PropertyLine
+import generators.unicode.hexToInt
+import generators.unicode.writeHeader
+import generators.unicode.writeIntArray
+import templates.KotlinTarget
+import java.io.File
+import java.io.FileWriter
+
+internal class OtherLowercaseRangesGenerator(
+    private val outputFile: File,
+    private val target: KotlinTarget
+) {
+    private val otherLowerRanges = mutableListOf<IntRange>()
+
+    fun appendLine(line: PropertyLine) {
+        // In Native the Other_Lowercase code points are also used to perform String.lowercase()
+        if (target != KotlinTarget.Native && line.rangeStart.hexToInt() > 0xFFFF) return
+
+        if (line.property == "Other_Lowercase") {
+            otherLowerRanges.add(line.intRange())
+        }
+    }
+
+    fun generate() {
+        val strategy = RangesWritingStrategy.of(target, "OtherLowercase")
+
+        FileWriter(outputFile).use { writer ->
+            writer.writeHeader(outputFile, "kotlin.text")
+            writer.appendLine()
+            strategy.beforeWritingRanges(writer)
+            writer.writeIntArray("otherLowerStart", otherLowerRanges.map { it.first }, strategy)
+            writer.writeIntArray("otherLowerLength", otherLowerRanges.map { it.last - it.first + 1 }, strategy, useHex = false)
+            strategy.afterWritingRanges(writer)
+            writer.appendLine()
+            writer.appendLine(isOtherLowercaseImpl(strategy))
+        }
+    }
+
+    fun isOtherLowercaseImpl(strategy: RangesWritingStrategy) = """
+        internal fun Int.isOtherLowercase(): Boolean {
+            val index = binarySearchRange(${strategy.rangeRef("otherLowerStart")}, this)
+            return index >= 0 && this < ${strategy.rangeRef("otherLowerStart")}[index] + ${strategy.rangeRef("otherLowerLength")}[index]
+        }
+    """.trimIndent()
+}
\ No newline at end of file
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherUppercaseRangesGenerator.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherUppercaseRangesGenerator.kt
new file mode 100644
index 00000000000..8fc794977ad
--- /dev/null
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/OtherUppercaseRangesGenerator.kt
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package generators.unicode.ranges
+
+import generators.unicode.PropertyLine
+import generators.unicode.hexToInt
+import generators.unicode.rangeCheck
+import generators.unicode.writeHeader
+import templates.KotlinTarget
+import java.io.File
+import java.io.FileWriter
+
+internal class OtherUppercaseRangesGenerator(
+    private val outputFile: File,
+    private val target: KotlinTarget
+) {
+    private val otherUpperRanges = mutableListOf<IntRange>()
+
+    fun appendLine(line: PropertyLine) {
+        // In Native the Other_Uppercase code points are also used to perform String.lowercase()
+        if (target != KotlinTarget.Native && line.rangeStart.hexToInt() > 0xFFFF) return
+
+        if (line.property == "Other_Uppercase") {
+            otherUpperRanges.add(line.intRange())
+        }
+    }
+
+    fun generate() {
+        FileWriter(outputFile).use { writer ->
+            writer.writeHeader(outputFile, "kotlin.text")
+            writer.appendLine()
+            writer.appendLine(isOtherUppercaseImpl())
+        }
+    }
+
+    fun isOtherUppercaseImpl(): String {
+        val indent = "    ".repeat(5)
+        val builder = StringBuilder()
+
+        for (i in otherUpperRanges.indices) {
+            if (i != 0) {
+                builder.appendLine().append(indent).append("|| ")
+            }
+            builder.append(otherUpperRanges[i].rangeCheck("this", indent))
+        }
+
+        return """
+        internal fun Int.isOtherUppercase(): Boolean {
+            return $builder
+        }
+        """.trimIndent()
+    }
+}
\ No newline at end of file
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/LetterRangesWriter.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/LetterRangesWriter.kt
index 731d5c86483..872ab111f1c 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/LetterRangesWriter.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/LetterRangesWriter.kt
@@ -60,17 +60,17 @@ internal open class LetterRangesWriter(protected val strategy: RangesWritingStra
         }
 
         /**
-         * Returns `true` if this character is a lower case letter.
+         * Returns `true` if this character is a lower case letter, or it has contributory property Other_Lowercase.
          */
         internal fun Char.isLowerCaseImpl(): Boolean {
-            return getLetterType() == 1
+            return getLetterType() == 1 || code.isOtherLowercase()
         }
 
         /**
-         * Returns `true` if this character is an upper case letter.
+         * Returns `true` if this character is an upper case letter, or it has contributory property Other_Uppercase.
          */
         internal fun Char.isUpperCaseImpl(): Boolean {
-            return getLetterType() == 2
+            return getLetterType() == 2 || code.isOtherUppercase()
         }
 
         /**
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/WhitespaceRangesWriter.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/WhitespaceRangesWriter.kt
index 520b70bfd53..0715037ebf6 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/WhitespaceRangesWriter.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/unicode/ranges/writers/WhitespaceRangesWriter.kt
@@ -5,6 +5,7 @@
 
 package generators.unicode.ranges.writers
 
+import generators.unicode.rangeCheck
 import generators.unicode.toHexIntLiteral
 import java.io.FileWriter
 
@@ -38,24 +39,12 @@ internal class WhitespaceRangesWriter : RangesWriter {
 
             val start = rangeStart[i]
             val end = rangeEnd[i]
-            when (start) {
-                end -> {
-                    if (start > 0x1000 && tabCount == 5) {
-                        builder.appendLine("$ch > 0x1000 && (")
-                        tabCount = 6
-                        builder.append(tab.repeat(tabCount))
-                    }
-                    builder.appendLine("$ch == ${start.toHexIntLiteral()}")
-                }
-                end - 1 -> {
-                    builder.appendLine("$ch == ${start.toHexIntLiteral()}")
-                    builder.append(tab.repeat(tabCount)).append("|| ")
-                    builder.appendLine("$ch == ${end.toHexIntLiteral()}")
-                }
-                else -> {
-                    builder.appendLine("$ch in ${start.toHexIntLiteral()}..${end.toHexIntLiteral()}")
-                }
+            if (start > 0x1000 && tabCount == 5) {
+                builder.appendLine("$ch > 0x1000 && (")
+                tabCount = 6
+                builder.append(tab.repeat(tabCount))
             }
+            builder.appendLine((start..end).rangeCheck(ch, tab.repeat(tabCount)))
         }
 
         return builder.append(tab.repeat(5)).append(")").toString()