diff --git a/package-lock.json b/package-lock.json
index 06791bfa0b..11df78369e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,6 @@
         "dayjs": "1.11.8",
         "dompurify": "^2.3.1",
         "favico.js-slevomat": "^0.3.11",
-        "filesize": "^7.0.0",
         "jed": "1.1.1",
         "lit": "^2.4.0",
         "localforage-webextensionstorage-driver": "^3.0.0",
@@ -5278,11 +5277,11 @@
       }
     },
     "node_modules/filesize": {
-      "version": "7.0.0",
-      "resolved": "https://registry.npmjs.org/filesize/-/filesize-7.0.0.tgz",
-      "integrity": "sha512-Wsstw+O1lZ9gVmOI1thyeQvODsaoId2qw14lCqIzUhoHKXX7T2hVpB7BR6SvgodMBgWccrx/y2eyV8L7tDmY6A==",
+      "version": "10.0.7",
+      "resolved": "https://registry.npmjs.org/filesize/-/filesize-10.0.7.tgz",
+      "integrity": "sha512-iMRG7Qo9nayLoU3PNCiLizYtsy4W1ClrapeCwEgtiQelOAOuRJiw4QaLI+sSr8xr901dgHv+EYP2bCusGZgoiA==",
       "engines": {
-        "node": ">= 0.4.0"
+        "node": ">= 10.4.0"
       }
     },
     "node_modules/fill-range": {
@@ -11265,7 +11264,7 @@
         "@converse/skeletor": "0.0.8",
         "dayjs": "1.11.8",
         "dompurify": "^2.3.1",
-        "filesize": "^7.0.0",
+        "filesize": "^10.0.7",
         "localforage-webextensionstorage-driver": "^3.0.0",
         "lodash-es": "^4.17.21",
         "pluggable.js": "3.0.1",
diff --git a/package.json b/package.json
index 2476615e2f..d88f48980e 100644
--- a/package.json
+++ b/package.json
@@ -118,7 +118,6 @@
     "dayjs": "1.11.8",
     "dompurify": "^2.3.1",
     "favico.js-slevomat": "^0.3.11",
-    "filesize": "^7.0.0",
     "jed": "1.1.1",
     "lit": "^2.4.0",
     "localforage-webextensionstorage-driver": "^3.0.0",
diff --git a/src/headless/package.json b/src/headless/package.json
index bba2d7c0d3..4444423dc6 100644
--- a/src/headless/package.json
+++ b/src/headless/package.json
@@ -35,7 +35,7 @@
     "@converse/skeletor": "0.0.8",
     "dayjs": "1.11.8",
     "dompurify": "^2.3.1",
-    "filesize": "^7.0.0",
+    "filesize": "^10.0.7",
     "localforage-webextensionstorage-driver": "^3.0.0",
     "lodash-es": "^4.17.21",
     "pluggable.js": "3.0.1",
diff --git a/src/headless/plugins/chat/model.js b/src/headless/plugins/chat/model.js
index 96508ee7fb..78f22da801 100644
--- a/src/headless/plugins/chat/model.js
+++ b/src/headless/plugins/chat/model.js
@@ -1,5 +1,4 @@
 import ModelWithContact from './model-with-contact.js';
-import filesize from "filesize";
 import isMatch from "lodash-es/isMatch";
 import isObject from "lodash-es/isObject";
 import log from '@converse/headless/log';
@@ -8,6 +7,7 @@ import { Model } from '@converse/skeletor/src/model.js';
 import { TimeoutError } from '../../shared/errors.js';
 import { _converse, api, converse } from "../../core.js";
 import { debouncedPruneHistory, handleCorrection } from '@converse/headless/shared/chat/utils.js';
+import { filesize } from "filesize";
 import { getMediaURLsMetadata } from '@converse/headless/shared/parsers.js';
 import { getOpenPromise } from '@converse/openpromise';
 import { initStorage } from '@converse/headless/utils/storage.js';
diff --git a/src/headless/shared/api/public.js b/src/headless/shared/api/public.js
index adeed037e4..f38bc8f506 100644
--- a/src/headless/shared/api/public.js
+++ b/src/headless/shared/api/public.js
@@ -11,6 +11,7 @@ import { Collection } from "@converse/skeletor/src/collection";
 import { Model } from '@converse/skeletor/src/model.js';
 import { Strophe, $build, $iq, $msg, $pres } from 'strophe.js/src/strophe';
 import { TimeoutError } from '../errors.js';
+import { filesize } from 'filesize';
 import { html } from 'lit';
 import { initAppSettings } from '../settings/utils.js';
 import { sprintf } from 'sprintf-js';
@@ -200,6 +201,7 @@ export const converse = Object.assign(window.converse || {}, {
         URI,
         VERSION_NAME,
         dayjs,
+        filesize,
         html,
         log,
         sizzle,
diff --git a/src/plugins/chatview/tests/http-file-upload.js b/src/plugins/chatview/tests/http-file-upload.js
index f8d1444610..8bbd8f2563 100644
--- a/src/plugins/chatview/tests/http-file-upload.js
+++ b/src/plugins/chatview/tests/http-file-upload.js
@@ -391,7 +391,7 @@ describe("XEP-0363: HTTP File Upload", function () {
                     const messages = view.querySelectorAll('.message.chat-error');
                     expect(messages.length).toBe(1);
                     expect(messages[0].textContent.trim()).toBe(
-                        'The size of your file, my-juliet.jpg, exceeds the maximum allowed by your server, which is 5 MB.');
+                        'The size of your file, my-juliet.jpg, exceeds the maximum allowed by your server, which is 5.24 MB.');
                 }));
             });
         });
@@ -461,7 +461,7 @@ describe("XEP-0363: HTTP File Upload", function () {
                     await u.waitUntil(() => view.querySelector('.chat-content progress').getAttribute('value') === '0.5');
                     message.set('progress', 1);
                     await u.waitUntil(() => view.querySelector('.chat-content progress').getAttribute('value') === '1');
-                    expect(view.querySelector('.chat-content .chat-msg__text').textContent).toBe('Uploading file: my-juliet.jpg, 22.91 KB');
+                    expect(view.querySelector('.chat-content .chat-msg__text').textContent).toBe('Uploading file: my-juliet.jpg, 23.46 kB');
                     promise.resolve();
                 });
                 _converse.connection._dataRecv(mock.createRequest(stanza));
diff --git a/src/shared/chat/templates/file-progress.js b/src/shared/chat/templates/file-progress.js
index 5b0726bf28..325b2f92ec 100644
--- a/src/shared/chat/templates/file-progress.js
+++ b/src/shared/chat/templates/file-progress.js
@@ -1,8 +1,10 @@
 import 'shared/avatar/avatar.js';
-import filesize from 'filesize';
 import { __ } from 'i18n';
+import { converse } from '@converse/headless/core.js';
 import { html } from 'lit';
 
+const { filesize } = converse.env;
+
 export default (el) => {
     const i18n_uploading = __('Uploading file:');
     const filename = el.model.file.name;