diff --git a/extension/chrome/dev/ci_unit_test.htm b/extension/chrome/dev/ci_unit_test.htm
index 99d922bf1eb..f2fb005f2dc 100644
--- a/extension/chrome/dev/ci_unit_test.htm
+++ b/extension/chrome/dev/ci_unit_test.htm
@@ -27,7 +27,6 @@ <h1 id="h1">loading..</h1>
     <script src="/lib/zxcvbn-ts.js"></script>
     <script src="/lib/zxcvbn-language-common.js"></script>
     <script src="/lib/zxcvbn-language-en.js"></script>
-    <script src="/lib/iso-8859-2.js"></script>
     <script src="/lib/forge.js"></script>
     <script src="ci_unit_test.js" type="module"></script>
   </body>
diff --git a/extension/chrome/elements/compose.htm b/extension/chrome/elements/compose.htm
index 33a6b6deb99..7742c16341a 100644
--- a/extension/chrome/elements/compose.htm
+++ b/extension/chrome/elements/compose.htm
@@ -255,7 +255,6 @@ <h1 id="header_title" data-test="header-title">New Secure Message</h1>
     <script src="/lib/zxcvbn-ts.js"></script>
     <script src="/lib/zxcvbn-language-common.js"></script>
     <script src="/lib/zxcvbn-language-en.js"></script>
-    <script src="/lib/iso-8859-2.js"></script>
     <script src="/lib/forge.js"></script>
     <script src="/lib/linkify.min.js"></script>
     <script src="/lib/linkify-html.min.js"></script>
diff --git a/extension/chrome/settings/inbox/inbox.htm b/extension/chrome/settings/inbox/inbox.htm
index f11593a770b..c31af686e79 100644
--- a/extension/chrome/settings/inbox/inbox.htm
+++ b/extension/chrome/settings/inbox/inbox.htm
@@ -51,7 +51,6 @@ <h1></h1>
     <script src="/lib/purify.js"></script>
     <script src="/lib/jquery.min.js"></script>
     <script src="/lib/sweetalert2.js"></script>
-    <script src="/lib/iso-8859-2.js"></script>
     <script src="/lib/emailjs/punycode.js"></script>
     <script src="/lib/emailjs/emailjs-stringencoding.js"></script>
     <script src="/lib/emailjs/emailjs-mime-codec.js"></script>
diff --git a/extension/js/common/core/mime.ts b/extension/js/common/core/mime.ts
index 94f1d6b3219..9516aa67c34 100644
--- a/extension/js/common/core/mime.ts
+++ b/extension/js/common/core/mime.ts
@@ -4,7 +4,7 @@
 'use strict';
 
 import { Dict, Str } from './common.js';
-import { requireIso88592, requireMimeBuilder, requireMimeParser } from '../platform/require.js';
+import { requireMimeBuilder, requireMimeParser } from '../platform/require.js';
 
 import { Attachment } from './attachment.js';
 import { Buf } from './buf.js';
@@ -18,7 +18,6 @@ import { iso2022jpToUtf } from '../platform/util.js';
 /* eslint-disable @typescript-eslint/naming-convention */
 const MimeParser = requireMimeParser();
 const MimeBuilder = requireMimeBuilder();
-const Iso88592 = requireIso88592();
 /* eslint-enable @typescript-eslint/naming-convention */
 
 type AddressHeader = { address: string; name: string };
@@ -480,9 +479,12 @@ export class Mime {
   }
 
   private static getNodeContentAsUtfStr(node: MimeParserNode): string {
-    if (node.charset && Iso88592.labels.includes(node.charset)) {
-      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-      return Iso88592.decode(node.rawContent!);
+    // List of charset labels that map to ISO-8859-2
+    const iso88592Labels = ['csisolatin2', 'iso-8859-2', 'iso-ir-101', 'iso8859-2', 'iso88592', 'iso_8859-2', 'iso_8859-2:1987', 'l2', 'latin2'];
+    
+    if (node.charset && node.rawContent && iso88592Labels.includes(node.charset.toLowerCase())) {
+      const decoder = new TextDecoder('iso-8859-2');
+      return decoder.decode(Buf.fromRawBytesStr(node.rawContent));
     }
     let resultBuf: Buf;
     if (node.charset === 'utf-8' && node.contentTransferEncoding.value === 'base64') {
diff --git a/extension/js/common/platform/require.ts b/extension/js/common/platform/require.ts
index 0143ef7d6f1..8a408006499 100644
--- a/extension/js/common/platform/require.ts
+++ b/extension/js/common/platform/require.ts
@@ -25,12 +25,6 @@ import { MimeParser } from '../core/types/emailjs.js';
 import * as openpgp from 'openpgp';
 import { Catch } from './catch.js';
 
-type Codec = {
-  encode: (text: string, mode: 'fatal' | 'html') => string;
-  decode: (text: string) => string;
-  labels: string[];
-  version: string;
-};
 
 export const requireOpenpgp = () => {
   if (typeof window !== 'undefined' && typeof globalThis !== 'undefined' && window !== globalThis && Catch.browser().name === 'firefox') {
@@ -52,8 +46,3 @@ export const requireMimeParser = (): typeof MimeParser => {
 export const requireMimeBuilder = () => {
   return (globalThis as any)['emailjs-mime-builder']; // eslint-disable-line
 };
-
-export const requireIso88592 = (): Codec => {
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-member-access
-  return (globalThis as any).iso88592 as Codec;
-};
diff --git a/extension/manifest.json b/extension/manifest.json
index 176223d2b23..6f547d78b44 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -48,7 +48,6 @@
         "/lib/sweetalert2.js",
         "/lib/streams_web.js",
         "/lib/emailjs/punycode.js",
-        "/lib/iso-8859-2.js",
         "/lib/trusted-types.js",
         "/lib/emailjs/emailjs-stringencoding.js",
         "/lib/emailjs/emailjs-mime-codec.js",
diff --git a/package-lock.json b/package-lock.json
index ba36366ee40..eaf5dcb9be7 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,6 @@
         "filesize": "11.0.13",
         "fs-extra": "^11.3.2",
         "globby": "^15.0.0",
-        "iso-8859-2": "1.0.0",
         "jquery": "3.7.1",
         "linkify-html": "4.3.2",
         "linkifyjs": "4.3.2",
@@ -2258,6 +2257,29 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/addons-linter/node_modules/node-fetch": {
+      "version": "2.6.11",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.11.tgz",
+      "integrity": "sha512-4I6pdBY1EthSqDmJkiNk3JIT8cswwR9nfeW/cPdUagJYEQG7R95WRH74wpz7ma8Gh/9dI9FP+OU+0E4FvtA55w==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true,
+      "peer": true,
+      "dependencies": {
+        "whatwg-url": "^5.0.0"
+      },
+      "engines": {
+        "node": "4.x || >=6.0.0"
+      },
+      "peerDependencies": {
+        "encoding": "^0.1.0"
+      },
+      "peerDependenciesMeta": {
+        "encoding": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/addons-linter/node_modules/pino": {
       "version": "9.13.0",
       "resolved": "https://registry.npmjs.org/pino/-/pino-9.13.0.tgz",
@@ -6478,12 +6500,6 @@
       "dev": true,
       "license": "ISC"
     },
-    "node_modules/iso-8859-2": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/iso-8859-2/-/iso-8859-2-1.0.0.tgz",
-      "integrity": "sha512-4nenvssneZugAuUaIJwO2kBlRW5P1m4w2BrUhDGc9iiojH6cS4NlOP64JRBOnHCl7YgeV2cxNLehTzTR1aCKOg==",
-      "license": "MIT"
-    },
     "node_modules/isobject": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/isobject/-/isobject-3.0.1.tgz",
@@ -10460,6 +10476,15 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/tr46": {
+      "version": "0.0.3",
+      "resolved": "https://registry.npmjs.org/tr46/-/tr46-0.0.3.tgz",
+      "integrity": "sha512-N3WMsuqV66lT30CrXNbEjx4GEwlow3v6rr4mCcv6prnfwhS01rkgyFdjPNBYd9br7LpXV1+Emh01fHnq2Gdgrw==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true,
+      "peer": true
+    },
     "node_modules/ts-api-utils": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/ts-api-utils/-/ts-api-utils-2.1.0.tgz",
@@ -10842,6 +10867,15 @@
       "dev": true,
       "license": "Apache-2.0"
     },
+    "node_modules/webidl-conversions": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-3.0.1.tgz",
+      "integrity": "sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "optional": true,
+      "peer": true
+    },
     "node_modules/webpack": {
       "version": "5.102.1",
       "resolved": "https://registry.npmjs.org/webpack/-/webpack-5.102.1.tgz",
@@ -11030,6 +11064,19 @@
         "node": ">=18"
       }
     },
+    "node_modules/whatwg-url": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/whatwg-url/-/whatwg-url-5.0.0.tgz",
+      "integrity": "sha512-saE57nupxk6v3HY35+jzBwYa0rKSy0XR8JSxZPwgLr7ys0IBzhGviA1/TUGJLmSVqs8pb9AnvICXEuOHLprYTw==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true,
+      "peer": true,
+      "dependencies": {
+        "tr46": "~0.0.3",
+        "webidl-conversions": "^3.0.0"
+      }
+    },
     "node_modules/when": {
       "version": "3.7.7",
       "resolved": "https://registry.npmjs.org/when/-/when-3.7.7.tgz",
diff --git a/package.json b/package.json
index f137dc448d5..9be792e313a 100644
--- a/package.json
+++ b/package.json
@@ -53,7 +53,6 @@
     "filesize": "11.0.13",
     "fs-extra": "^11.3.2",
     "globby": "^15.0.0",
-    "iso-8859-2": "1.0.0",
     "jquery": "3.7.1",
     "linkify-html": "4.3.2",
     "linkifyjs": "4.3.2",
diff --git a/scripts/build.js b/scripts/build.js
index 7a7de863b77..b6c93afa96c 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -57,7 +57,6 @@ const copyDependencies = async () => {
     ['linkify-html/dist/linkify-html.min.js', 'lib/linkify-html.min.js'],
     ['sweetalert2/dist/sweetalert2.js', 'lib/sweetalert2.js'],
     ['sweetalert2/dist/sweetalert2.css', 'css/sweetalert2.css'],
-    ['iso-8859-2/iso-8859-2.js', 'lib/iso-8859-2.js'],
     ['@zxcvbn-ts/core/dist/zxcvbn-ts.js', 'lib/zxcvbn-ts.js'],
     ['@zxcvbn-ts/language-common/dist/zxcvbn-ts.js', 'lib/zxcvbn-language-common.js'],
     ['@zxcvbn-ts/language-en/dist/zxcvbn-ts.js', 'lib/zxcvbn-language-en.js'],
diff --git a/test/source/platform/require.ts b/test/source/platform/require.ts
index 94b23c38dc3..fe793c61043 100644
--- a/test/source/platform/require.ts
+++ b/test/source/platform/require.ts
@@ -21,8 +21,4 @@ export const requireMimeBuilder = (): any => {
   return undefined; // todo
 };
 
-export const requireIso88592 = (): any => {
-  // (window as any).iso88592
-  return undefined; // todo
-};
 /* eslint-enable @typescript-eslint/no-explicit-any */
diff --git a/tsconfig.json b/tsconfig.json
index 4d577739d7a..9c718c88b26 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -24,7 +24,6 @@
       "dompurify": ["../node_modules/dompurify/dist/purify.cjs.d.ts", "lib/purify.js", "COMMENT"],
       "fine-uploader": ["lib/fine-uploader.js", "COMMENT"],
       "filesize": ["lib/filesize.js", "../node_modules/filesize/types/filesize.d.ts"],
-      "iso-8859-2": ["lib/iso-8859-2.js", "COMMENT"],
       "emailjs-mime-parser": ["lib/emailjs/emailjs-mime-parser.js", "COMMENT"],
       "emailjs-mime-builder": ["lib/emailjs/emailjs-mime-builder.js", "COMMENT"],
       "node-forge": ["./extension/types/node-forge.d.ts", "lib/forge.mjs"],