diff --git a/test/fixtures/wpt/README.md b/test/fixtures/wpt/README.md
index eacd81cd69f712..2c8a8b9b03afa9 100644
--- a/test/fixtures/wpt/README.md
+++ b/test/fixtures/wpt/README.md
@@ -15,7 +15,7 @@ Last update:
 - console: https://github.com/web-platform-tests/wpt/tree/767ae35464/console
 - dom/abort: https://github.com/web-platform-tests/wpt/tree/0143fe244b/dom/abort
 - dom/events: https://github.com/web-platform-tests/wpt/tree/0a811c5161/dom/events
-- encoding: https://github.com/web-platform-tests/wpt/tree/5aa50dd415/encoding
+- encoding: https://github.com/web-platform-tests/wpt/tree/1ac8deee08/encoding
 - fetch/data-urls/resources: https://github.com/web-platform-tests/wpt/tree/7c79d998ff/fetch/data-urls/resources
 - FileAPI: https://github.com/web-platform-tests/wpt/tree/cceaf3628d/FileAPI
 - hr-time: https://github.com/web-platform-tests/wpt/tree/34cafd797e/hr-time
diff --git a/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-decoder.any.js b/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-decoder.any.js
index fca68358623bd9..aa226e185be7ca 100644
--- a/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-decoder.any.js
+++ b/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-decoder.any.js
@@ -66,24 +66,24 @@ decode([0xFE, 0x6D], "\u9FB8", "GB18030-2022 15");
 decode([0xFE, 0x7E], "\u9FB9", "GB18030-2022 16");
 decode([0xFE, 0x90], "\u9FBA", "GB18030-2022 17");
 decode([0xFE, 0xA0], "\u9FBB", "GB18030-2022 18");
-decode([0x82, 0x35, 0x90, 0x37], "\uE81E", "GB18030-2022 19");
-decode([0x82, 0x35, 0x90, 0x38], "\uE826", "GB18030-2022 20");
-decode([0x82, 0x35, 0x90, 0x39], "\uE82B", "GB18030-2022 21");
-decode([0x82, 0x35, 0x91, 0x30], "\uE82C", "GB18030-2022 22");
-decode([0x82, 0x35, 0x91, 0x31], "\uE832", "GB18030-2022 23");
-decode([0x82, 0x35, 0x91, 0x32], "\uE843", "GB18030-2022 24");
-decode([0x82, 0x35, 0x91, 0x33], "\uE854", "GB18030-2022 25");
-decode([0x82, 0x35, 0x91, 0x34], "\uE864", "GB18030-2022 26");
-decode([0x84, 0x31, 0x82, 0x36], "\uE78D", "GB18030-2022 27");
-decode([0x84, 0x31, 0x82, 0x37], "\uE78F", "GB18030-2022 28");
-decode([0x84, 0x31, 0x82, 0x38], "\uE78E", "GB18030-2022 29");
-decode([0x84, 0x31, 0x82, 0x39], "\uE790", "GB18030-2022 30");
-decode([0x84, 0x31, 0x83, 0x30], "\uE791", "GB18030-2022 31");
-decode([0x84, 0x31, 0x83, 0x31], "\uE792", "GB18030-2022 32");
-decode([0x84, 0x31, 0x83, 0x32], "\uE793", "GB18030-2022 33");
-decode([0x84, 0x31, 0x83, 0x33], "\uE794", "GB18030-2022 34");
-decode([0x84, 0x31, 0x83, 0x34], "\uE795", "GB18030-2022 35");
-decode([0x84, 0x31, 0x83, 0x35], "\uE796", "GB18030-2022 36");
+decode([0x82, 0x35, 0x90, 0x37], "\u9FB4", "GB18030-2022 19");
+decode([0x82, 0x35, 0x90, 0x38], "\u9FB5", "GB18030-2022 20");
+decode([0x82, 0x35, 0x90, 0x39], "\u9FB6", "GB18030-2022 21");
+decode([0x82, 0x35, 0x91, 0x30], "\u9FB7", "GB18030-2022 22");
+decode([0x82, 0x35, 0x91, 0x31], "\u9FB8", "GB18030-2022 23");
+decode([0x82, 0x35, 0x91, 0x32], "\u9FB9", "GB18030-2022 24");
+decode([0x82, 0x35, 0x91, 0x33], "\u9FBA", "GB18030-2022 25");
+decode([0x82, 0x35, 0x91, 0x34], "\u9FBB", "GB18030-2022 26");
+decode([0x84, 0x31, 0x82, 0x36], "\uFE10", "GB18030-2022 27");
+decode([0x84, 0x31, 0x82, 0x37], "\uFE11", "GB18030-2022 28");
+decode([0x84, 0x31, 0x82, 0x38], "\uFE12", "GB18030-2022 29");
+decode([0x84, 0x31, 0x82, 0x39], "\uFE13", "GB18030-2022 30");
+decode([0x84, 0x31, 0x83, 0x30], "\uFE14", "GB18030-2022 31");
+decode([0x84, 0x31, 0x83, 0x31], "\uFE15", "GB18030-2022 32");
+decode([0x84, 0x31, 0x83, 0x32], "\uFE16", "GB18030-2022 33");
+decode([0x84, 0x31, 0x83, 0x33], "\uFE17", "GB18030-2022 34");
+decode([0x84, 0x31, 0x83, 0x34], "\uFE18", "GB18030-2022 35");
+decode([0x84, 0x31, 0x83, 0x35], "\uFE19", "GB18030-2022 36");
 
 let i = 0;
 for (const range of ranges) {
diff --git a/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-encoder.html b/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-encoder.html
index 531d26084e27dc..dc0dc43468f248 100644
--- a/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-encoder.html
+++ b/test/fixtures/wpt/encoding/legacy-mb-schinese/gb18030/gb18030-encoder.html
@@ -43,24 +43,24 @@
  encode("\u9FB9", "%FE~", "GB18030-2022 16");
  encode("\u9FBA", "%FE%90", "GB18030-2022 17");
  encode("\u9FBB", "%FE%A0", "GB18030-2022 18");
- encode("\uE78D", "%841%826", "GB18030-2022 19");
- encode("\uE78E", "%841%828", "GB18030-2022 20");
- encode("\uE78F", "%841%827", "GB18030-2022 21");
- encode("\uE790", "%841%829", "GB18030-2022 22");
- encode("\uE791", "%841%830", "GB18030-2022 23");
- encode("\uE792", "%841%831", "GB18030-2022 24");
- encode("\uE793", "%841%832", "GB18030-2022 25");
- encode("\uE794", "%841%833", "GB18030-2022 26");
- encode("\uE795", "%841%834", "GB18030-2022 27");
- encode("\uE796", "%841%835", "GB18030-2022 28");
- encode("\uE81E", "%825%907", "GB18030-2022 29");
- encode("\uE826", "%825%908", "GB18030-2022 30");
- encode("\uE82B", "%825%909", "GB18030-2022 31");
- encode("\uE82C", "%825%910", "GB18030-2022 32");
- encode("\uE832", "%825%911", "GB18030-2022 33");
- encode("\uE843", "%825%912", "GB18030-2022 34");
- encode("\uE854", "%825%913", "GB18030-2022 35");
- encode("\uE864", "%825%914", "GB18030-2022 36");
+ encode("\uE78D", "%A6%D9", "GB18030-2022 19");
+ encode("\uE78E", "%A6%DA", "GB18030-2022 20");
+ encode("\uE78F", "%A6%DB", "GB18030-2022 21");
+ encode("\uE790", "%A6%DC", "GB18030-2022 22");
+ encode("\uE791", "%A6%DD", "GB18030-2022 23");
+ encode("\uE792", "%A6%DE", "GB18030-2022 24");
+ encode("\uE793", "%A6%DF", "GB18030-2022 25");
+ encode("\uE794", "%A6%EC", "GB18030-2022 26");
+ encode("\uE795", "%A6%ED", "GB18030-2022 27");
+ encode("\uE796", "%A6%F3", "GB18030-2022 28");
+ encode("\uE81E", "%FEY", "GB18030-2022 29");
+ encode("\uE826", "%FEa", "GB18030-2022 30");
+ encode("\uE82B", "%FEf", "GB18030-2022 31");
+ encode("\uE82C", "%FEg", "GB18030-2022 32");
+ encode("\uE832", "%FEm", "GB18030-2022 33");
+ encode("\uE843", "%FE~", "GB18030-2022 34");
+ encode("\uE854", "%FE%90", "GB18030-2022 35");
+ encode("\uE864", "%FE%A0", "GB18030-2022 36");
 
  const upperCaseNibble = x => {
    return Math.floor(x).toString(16).toUpperCase();
diff --git a/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-decoder.any.js b/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-decoder.any.js
index c0221480da156d..b7f1ca9c51e88f 100644
--- a/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-decoder.any.js
+++ b/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-decoder.any.js
@@ -1,3 +1,5 @@
+// Additional tests can be found in ../gb18030/gb18030-decoder.any.js
+
 const gbkPointers = [
     6432, 7533, 7536, 7672, 7673, 7674, 7675, 7676, 7677, 7678, 7679, 7680, 7681, 7682, 7683, 7684,
     23766, 23770, 23771, 23772, 23773, 23774, 23776, 23777, 23778, 23779, 23780, 23781, 23782, 23784, 23785, 23786,
diff --git a/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-encoder.html b/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-encoder.html
index e43cb73fea72e5..11557242e3dc65 100644
--- a/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-encoder.html
+++ b/test/fixtures/wpt/encoding/legacy-mb-schinese/gbk/gbk-encoder.html
@@ -23,4 +23,43 @@
  encode("\u00A5", "%26%23165%3B", "legacy WebKit case 1");
  encode("\u22EF", "%26%238943%3B", "legacy WebKit case 2");
  encode("\u301C", "%26%2312316%3B", "legacy WebKit case 3");
+ encode("\u{10FFFF}", "%26%231114111%3B", "U+10FFFF");
+
+  // GB18030-2022
+ encode("\uFE10", "%A6%D9", "GB18030-2022 1");
+ encode("\uFE12", "%A6%DA", "GB18030-2022 2");
+ encode("\uFE11", "%A6%DB", "GB18030-2022 3");
+ encode("\uFE13", "%A6%DC", "GB18030-2022 4");
+ encode("\uFE14", "%A6%DD", "GB18030-2022 5");
+ encode("\uFE15", "%A6%DE", "GB18030-2022 6");
+ encode("\uFE16", "%A6%DF", "GB18030-2022 7");
+ encode("\uFE17", "%A6%EC", "GB18030-2022 8");
+ encode("\uFE18", "%A6%ED", "GB18030-2022 9");
+ encode("\uFE19", "%A6%F3", "GB18030-2022 10");
+ encode("\u9FB4", "%FEY", "GB18030-2022 11");
+ encode("\u9FB5", "%FEa", "GB18030-2022 12");
+ encode("\u9FB6", "%FEf", "GB18030-2022 13");
+ encode("\u9FB7", "%FEg", "GB18030-2022 14");
+ encode("\u9FB8", "%FEm", "GB18030-2022 15");
+ encode("\u9FB9", "%FE~", "GB18030-2022 16");
+ encode("\u9FBA", "%FE%90", "GB18030-2022 17");
+ encode("\u9FBB", "%FE%A0", "GB18030-2022 18");
+ encode("\uE78D", "%A6%D9", "GB18030-2022 19");
+ encode("\uE78E", "%A6%DA", "GB18030-2022 20");
+ encode("\uE78F", "%A6%DB", "GB18030-2022 21");
+ encode("\uE790", "%A6%DC", "GB18030-2022 22");
+ encode("\uE791", "%A6%DD", "GB18030-2022 23");
+ encode("\uE792", "%A6%DE", "GB18030-2022 24");
+ encode("\uE793", "%A6%DF", "GB18030-2022 25");
+ encode("\uE794", "%A6%EC", "GB18030-2022 26");
+ encode("\uE795", "%A6%ED", "GB18030-2022 27");
+ encode("\uE796", "%A6%F3", "GB18030-2022 28");
+ encode("\uE81E", "%FEY", "GB18030-2022 29");
+ encode("\uE826", "%FEa", "GB18030-2022 30");
+ encode("\uE82B", "%FEf", "GB18030-2022 31");
+ encode("\uE82C", "%FEg", "GB18030-2022 32");
+ encode("\uE832", "%FEm", "GB18030-2022 33");
+ encode("\uE843", "%FE~", "GB18030-2022 34");
+ encode("\uE854", "%FE%90", "GB18030-2022 35");
+ encode("\uE864", "%FE%A0", "GB18030-2022 36");
 </script>
diff --git a/test/fixtures/wpt/encoding/resources/utf-32-big-endian-nobom.xml b/test/fixtures/wpt/encoding/resources/utf-32-big-endian-nobom.xml
index f51213c965ce74..f704501ccae0d6 100644
Binary files a/test/fixtures/wpt/encoding/resources/utf-32-big-endian-nobom.xml and b/test/fixtures/wpt/encoding/resources/utf-32-big-endian-nobom.xml differ
diff --git a/test/fixtures/wpt/encoding/resources/utf-32-little-endian-nobom.xml b/test/fixtures/wpt/encoding/resources/utf-32-little-endian-nobom.xml
index 64e6051a2c6b07..465f44df5f782a 100644
Binary files a/test/fixtures/wpt/encoding/resources/utf-32-little-endian-nobom.xml and b/test/fixtures/wpt/encoding/resources/utf-32-little-endian-nobom.xml differ
diff --git a/test/fixtures/wpt/versions.json b/test/fixtures/wpt/versions.json
index a81bc3ab8b5b60..a93ad1762feb80 100644
--- a/test/fixtures/wpt/versions.json
+++ b/test/fixtures/wpt/versions.json
@@ -20,7 +20,7 @@
     "path": "dom/events"
   },
   "encoding": {
-    "commit": "5aa50dd4151b5bc1d04d5505366c6e27df30af5b",
+    "commit": "1ac8deee082ecfb5d3b6f9c56cf9d1688a2fc218",
     "path": "encoding"
   },
   "fetch/data-urls/resources": {