diff --git a/js/pkg/twitter-text-1.14.8.js b/js/pkg/twitter-text-1.14.8.js
diff --git a/js/pkg/twitter-text-1.14.8.min.js b/js/pkg/twitter-text-1.14.8.min.js
diff --git a/js/twitter-text.js b/js/twitter-text.js
@@ -66,6 +66,9 @@
  twttr.txt.regexen.rtl_chars = /[\u0600-\u06FF]|[\u0750-\u077F]|[\u0590-\u05FF]|[\uFE70-\uFEFF]/mg;
  twttr.txt.regexen.non_bmp_code_pairs = /[\uD800-\uDBFF][\uDC00-\uDFFF]/mg;
+  
+  // [\uFF00-\uFFEF] : Full-width roman + half-width katakana
+  
+  twttr.txt.regexen.cjk_chars = /[\u2E80-\u2EFF]|[\u2F00-\u2FDF]|[\u2FF0-\u2FFF]|[\u3000-\u303F]|[\u3040-\u309F]|[\u30A0-\u30FF]|[\u3100-\u312F]|[\u3130-\u318F]|[\u3190-\u319F]|[\u31A0-\u31BF]|[\u31C0-\u31EF]|[\u31F0-\u31FF]|[\u3200-\u32FF]|[\u3300-\u33FF]|[\u3400-\u4DBF]|[\u4DC0-\u4DFF]|[\u4E00-\u9FFF]|[\uFF00-\uFFEF]/mg;
+  
+
  twttr.txt.regexen.latinAccentChars = /\xC0-\xD6\xD8-\xF6\xF8-\xFF\u0100-\u024F\u0253\u0254\u0256\u0257\u0259\u025B\u0263\u0268\u026F\u0272\u0289\u028B\u02BB\u0300-\u036F\u1E00-\u1EFF/;
  // Generated from unicode_regex/unicode_regex_groups.scala, same as objective c's \p{L}\p{M}
@@ -993,7 +996,9 @@
  };
  twttr.txt.getUnicodeTextLength = function(text) {
-  
-    return text.replace(twttr.txt.regexen.non_bmp_code_pairs, ' ').length;
+  
+    return text
+  
+      .replace(twttr.txt.regexen.cjk_chars, '  ')
+  
+      .replace(twttr.txt.regexen.non_bmp_code_pairs, ' ').length;
  };
  twttr.txt.convertUnicodeIndices = function(text, entities, indicesInUTF16) {
@@ -1148,7 +1153,7 @@
    return result;
  };
-  
-  var MAX_LENGTH = 140;
+  
+  var MAX_LENGTH = 280;
  // Returns the length of Tweet text with consideration to t.co URL replacement
  // and chars outside the basic multilingual plane that use 2 UTF16 code points
diff --git a/objc/lib/TwitterText.m b/objc/lib/TwitterText.m
@@ -319,7 +319,7 @@
 #pragma mark - Constants
-  
-static const NSInteger MaxTweetLength = 140;
+  
+static const NSInteger MaxTweetLength = 280;
 static const NSInteger HTTPShortURLLength = 23;
 static const NSInteger HTTPSShortURLLength = 23;
diff --git a/objc/tests/TwitterTextTests.m b/objc/tests/TwitterTextTests.m
@@ -18,7 +18,7 @@ @implementation TwitterTextTests
 - (void)testRemainingCharacterCountForLongTweet
 {
-  
-    XCTAssertEqual([TwitterText remainingCharacterCount:@"123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890" httpURLLength:23 httpsURLLength:23], -10);
+  
+    XCTAssertEqual([TwitterText remainingCharacterCount:@"12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567891" httpURLLength:23 httpsURLLength:23], -10);
 }
 - (void)testHashtagBoundary
diff --git a/objc/tests/json-conformance/validate.json b/objc/tests/json-conformance/validate.json
@@ -7,22 +7,22 @@
        "expected": true
      },
      {
-  
-        "description": "Valid Tweet: 140 characters",
+  
+        "description": "Valid Tweet: 280 characters",
        "text": "A lie gets halfway around the world before the truth has a chance to get its pants on. Winston Churchill (1874-1965) http://bit.ly/dJpywL",
        "expected": true
      },
      {
-  
-        "description": "Valid Tweet: 140 characters (with accents)",
+  
+        "description": "Valid Tweet: 280 characters (with accents)",
        "text": "A lié géts halfway arøünd thé wørld béføré thé truth has a chance tø get its pants øn. Winston Churchill (1874-1965) http://bit.ly/dJpywL",
        "expected": true
      },
      {
-  
-        "description": "Valid Tweet: 140 characters (double byte characters)",
+  
+        "description": "Valid Tweet: 280 characters (double byte characters)",
        "text": "のののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののののの",
        "expected": true
      },
      {
-  
-        "description": "Valid Tweet: 140 characters (double word characters)",
+  
+        "description": "Valid Tweet: 280 characters (double word characters)",
        "text": "🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱🐱",
        "expected": true
      },
@@ -32,13 +32,13 @@
        "expected": false
      },
      {
-  
-        "description": "Invalid Tweet: 141 characters",
-  
-        "text": "A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill (1874-1965) http://bit.ly/dJpywL",
+  
+        "description": "Invalid Tweet: 281 characters",
+  
+        "text": "A lie gets halfway around the world before the truth has a chance to get its pants on. Winston Churchill (1874-1965) http://bit.ly/dJpywL A lie gets halfway around the world before the truth has a chance to get its pants on. Winston Churchill (1874-1965) http://bit.ly/dJpywL",
        "expected": false
      },
      {
-  
-        "description": "Invalid Tweet: 141 characters (due to newline)",
-  
-        "text": "A lie gets halfway around the world before the truth has a chance to get its pants on. \n- Winston Churchill (1874-1965) http://bit.ly/dJpywL",
+  
+        "description": "Invalid Tweet: 281 characters (due to newline)",
+  
+        "text": "A lie gets halfway around the world before the truth has a chance to get its pants on.\nWinston Churchill (1874-1965) http://bit.ly/dJpywL A lie gets halfway around the world before the truth has a chance to get its pants on. Winston Churchill (1874-1965) http://bit.ly/dJpywL",
        "expected": false
      }
    ],
diff --git a/rb/lib/twitter-text/validation.rb b/rb/lib/twitter-text/validation.rb
@@ -2,7 +2,7 @@
 module Twitter
  module Validation extend self
-  
-    MAX_LENGTH = 140
+  
+    MAX_LENGTH = 280
    DEFAULT_TCO_URL_LENGTHS = {
      :short_url_length => 23,
diff --git a/rb/spec/validation_spec.rb b/rb/spec/validation_spec.rb
@@ -26,18 +26,18 @@ class TestValidation
    TestValidation.new.tweet_invalid?("not-Unicode:\xfff0").should == :invalid_characters
  end
-  
-  it "should allow <= 140 combined accent characters" do
+  
+  it "should allow <= 280 combined accent characters" do
    char = [0x65, 0x0301].pack('U')
    TestValidation.new.tweet_invalid?(char * 139).should == false
-  
-    TestValidation.new.tweet_invalid?(char * 140).should == false
-  
-    TestValidation.new.tweet_invalid?(char * 141).should == :too_long
+  
+    TestValidation.new.tweet_invalid?(char * 280).should == false
+  
+    TestValidation.new.tweet_invalid?(char * 281).should == :too_long
  end
-  
-  it "should allow <= 140 multi-byte characters" do
+  
+  it "should allow <= 280 multi-byte characters" do
    char = [ 0x1d106 ].pack('U')
    TestValidation.new.tweet_invalid?(char * 139).should == false
-  
-    TestValidation.new.tweet_invalid?(char * 140).should == false
-  
-    TestValidation.new.tweet_invalid?(char * 141).should == :too_long
+  
+    TestValidation.new.tweet_invalid?(char * 280).should == false
+  
+    TestValidation.new.tweet_invalid?(char * 281).should == :too_long
  end
 end