diff --git a/.eslintrc.js b/.eslintrc.js
index df44d24e580..6110795d319 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -469,7 +469,7 @@ module.exports = {
     },
     {
       files: ['packages/@uppy/*/src/**/*.ts', 'packages/@uppy/*/src/**/*.tsx'],
-      excludedFiles: ['packages/@uppy/**/*.test.ts'],
+      excludedFiles: ['packages/@uppy/**/*.test.ts', 'packages/@uppy/core/src/mocks/*.ts'],
       rules: {
         '@typescript-eslint/explicit-function-return-type': 'error',
       },
diff --git a/package.json b/package.json
index 2b3b52a5a57..6d7b459eb38 100644
--- a/package.json
+++ b/package.json
@@ -152,7 +152,7 @@
     "test:locale-packs": "yarn locale-packs:unused && yarn locale-packs:warnings",
     "test:locale-packs:unused": "yarn workspace @uppy-dev/locale-pack test unused",
     "test:locale-packs:warnings": "yarn workspace @uppy-dev/locale-pack test warnings",
-    "test:unit": "yarn run build:lib && yarn test:watch",
+    "test:unit": "yarn run build:lib && yarn test:watch --run",
     "test:watch": "vitest --environment jsdom --dir packages/@uppy",
     "test": "npm-run-all lint test:locale-packs:unused test:unit test:type test:companion",
     "uploadcdn": "yarn node ./bin/upload-to-cdn.js",
diff --git a/packages/@uppy/companion-client/src/RequestClient.js b/packages/@uppy/companion-client/src/RequestClient.js
index ffaac2fd280..972315b8efd 100644
--- a/packages/@uppy/companion-client/src/RequestClient.js
+++ b/packages/@uppy/companion-client/src/RequestClient.js
@@ -55,9 +55,6 @@ async function handleJSONResponse (res) {
   throw new HttpError({ statusCode: res.status, message: errMsg })
 }
 
-// todo pull out into core instead?
-const allowedHeadersCache = new Map()
-
 export default class RequestClient {
   static VERSION = packageJson.version
 
@@ -84,11 +81,13 @@ export default class RequestClient {
     return stripSlash(companion && companion[host] ? companion[host] : host)
   }
 
-  async headers () {
+  async headers (emptyBody = false) {
     const defaultHeaders = {
       Accept: 'application/json',
-      'Content-Type': 'application/json',
-      'Uppy-Versions': `@uppy/companion-client=${RequestClient.VERSION}`,
+      ...(emptyBody ? undefined : {
+        // Passing those headers on requests with no data forces browsers to first make a preflight request.
+        'Content-Type': 'application/json',
+      }),
     }
 
     return {
@@ -117,88 +116,10 @@ export default class RequestClient {
     return `${this.hostname}/${url}`
   }
 
-  /*
-    Preflight was added to avoid breaking change between older Companion-client versions and
-    newer Companion versions and vice-versa. Usually the break will manifest via CORS errors because a
-    version of companion-client could be sending certain headers to a version of Companion server that
-    does not support those headers. In which case, the default preflight would lead to CORS.
-    So to avoid those errors, we do preflight ourselves, to see what headers the Companion server
-    we are communicating with allows. And based on that, companion-client knows what headers to
-    send and what headers to not send.
-
-    The preflight only happens once throughout the life-cycle of a certain
-    Companion-client <-> Companion-server pair (allowedHeadersCache).
-    Subsequent requests use the cached result of the preflight.
-    However if there is an error retrieving the allowed headers, we will try again next time
-  */
-  async preflight (path) {
-    const allowedHeadersCached = allowedHeadersCache.get(this.hostname)
-    if (allowedHeadersCached != null) return allowedHeadersCached
-
-    const fallbackAllowedHeaders = [
-      'accept',
-      'content-type',
-      'uppy-auth-token',
-    ]
-
-    const promise = (async () => {
-      try {
-        const response = await fetch(this.#getUrl(path), { method: 'OPTIONS' })
-
-        const header = response.headers.get('access-control-allow-headers')
-        if (header == null || header === '*') {
-          allowedHeadersCache.set(this.hostname, fallbackAllowedHeaders)
-          return fallbackAllowedHeaders
-        }
-
-        this.uppy.log(
-          `[CompanionClient] adding allowed preflight headers to companion cache: ${this.hostname} ${header}`,
-        )
-
-        const allowedHeaders = header
-          .split(',')
-          .map((headerName) => headerName.trim().toLowerCase())
-        allowedHeadersCache.set(this.hostname, allowedHeaders)
-        return allowedHeaders
-      } catch (err) {
-        this.uppy.log(
-          `[CompanionClient] unable to make preflight request ${err}`,
-          'warning',
-        )
-        // If the user gets a network error or similar, we should try preflight
-        // again next time, or else we might get incorrect behaviour.
-        allowedHeadersCache.delete(this.hostname) // re-fetch next time
-        return fallbackAllowedHeaders
-      }
-    })()
-
-    allowedHeadersCache.set(this.hostname, promise)
-    return promise
-  }
-
-  async preflightAndHeaders (path) {
-    const [allowedHeaders, headers] = await Promise.all([
-      this.preflight(path),
-      this.headers(),
-    ])
-    // filter to keep only allowed Headers
-    return Object.fromEntries(
-      Object.entries(headers).filter(([header]) => {
-        if (!allowedHeaders.includes(header.toLowerCase())) {
-          this.uppy.log(
-            `[CompanionClient] excluding disallowed header ${header}`,
-          )
-          return false
-        }
-        return true
-      }),
-    )
-  }
-
   /** @protected */
   async request ({ path, method = 'GET', data, skipPostResponse, signal }) {
     try {
-      const headers = await this.preflightAndHeaders(path)
+      const headers = await this.headers(!data)
       const response = await fetchWithNetworkError(this.#getUrl(path), {
         method,
         signal,
@@ -280,7 +201,7 @@ export default class RequestClient {
               || (err.statusCode >= 500 && err.statusCode <= 599 && ![501, 505].includes(err.statusCode))
             )
             if (err instanceof HttpError && !isRetryableHttpError()) throw new AbortError(err);
-  
+
             // p-retry will retry most other errors,
             // but it will not retry TypeError (except network error TypeErrors)
             throw err
@@ -359,7 +280,7 @@ export default class RequestClient {
           socket.send(JSON.stringify({
             action,
             payload: payload ?? {},
-          }))    
+          }))
         };
 
         function sendState() {
@@ -379,7 +300,7 @@ export default class RequestClient {
             socketAbortController?.abort?.()
             reject(err)
           }
-  
+
           // todo instead implement the ability for users to cancel / retry *currently uploading files* in the UI
           function resetActivityTimeout() {
             clearTimeout(activityTimeout)
@@ -414,7 +335,7 @@ export default class RequestClient {
 
                   try {
                     const { action, payload } = JSON.parse(e.data)
-            
+
                     switch (action) {
                       case 'progress': {
                         emitSocketProgress(this, payload, file)
@@ -430,8 +351,8 @@ export default class RequestClient {
                         const { message } = payload.error
                         throw Object.assign(new Error(message), { cause: payload.error })
                       }
-                        default:
-                          this.uppy.log(`Companion socket unknown action ${action}`, 'warning')
+                      default:
+                        this.uppy.log(`Companion socket unknown action ${action}`, 'warning')
                     }
                   } catch (err) {
                     onFatalError(err)
@@ -444,7 +365,7 @@ export default class RequestClient {
                   if (socket) socket.close()
                   socket = undefined
                 }
-        
+
                 socketAbortController.signal.addEventListener('abort', () => {
                   closeSocket()
                 })
diff --git a/packages/@uppy/companion/package.json b/packages/@uppy/companion/package.json
index 3b39dd146c6..8e28728c101 100644
--- a/packages/@uppy/companion/package.json
+++ b/packages/@uppy/companion/package.json
@@ -63,7 +63,6 @@
     "node-schedule": "2.1.0",
     "prom-client": "14.0.1",
     "redis": "4.2.0",
-    "semver": "7.5.3",
     "serialize-error": "^2.1.0",
     "serialize-javascript": "^6.0.0",
     "tus-js-client": "^3.0.0",
diff --git a/packages/@uppy/companion/src/config/companion.js b/packages/@uppy/companion/src/config/companion.js
index 59c4f0c9916..4ad236f76ae 100644
--- a/packages/@uppy/companion/src/config/companion.js
+++ b/packages/@uppy/companion/src/config/companion.js
@@ -18,7 +18,6 @@ const defaultOptions = {
   },
   enableUrlEndpoint: true, // todo next major make this default false
   allowLocalUrls: false,
-  logClientVersion: true,
   periodicPingUrls: [],
   streamingUpload: false,
   clientSocketConnectTimeout: 60000,
diff --git a/packages/@uppy/companion/src/server/controllers/connect.js b/packages/@uppy/companion/src/server/controllers/connect.js
index 1e98927744c..7e8f9b8e5dd 100644
--- a/packages/@uppy/companion/src/server/controllers/connect.js
+++ b/packages/@uppy/companion/src/server/controllers/connect.js
@@ -19,10 +19,6 @@ module.exports = function connect (req, res) {
     state = oAuthState.addToState(state, { companionInstance: req.companion.buildURL('', true) }, secret)
   }
 
-  if (req.companion.clientVersion) {
-    state = oAuthState.addToState(state, { clientVersion: req.companion.clientVersion }, secret)
-  }
-
   if (req.query.uppyPreAuthToken) {
     state = oAuthState.addToState(state, { preAuthToken: req.query.uppyPreAuthToken }, secret)
   }
diff --git a/packages/@uppy/companion/src/server/helpers/version.js b/packages/@uppy/companion/src/server/helpers/version.js
deleted file mode 100644
index f2b0dc2bb20..00000000000
--- a/packages/@uppy/companion/src/server/helpers/version.js
+++ /dev/null
@@ -1,15 +0,0 @@
-const semver = require('semver')
-
-/**
- * checks if a version is greater than or equal to
- *
- * @param {string} v1 the LHS version
- * @param {string} v2 the RHS version
- * @returns {boolean}
- */
-exports.gte = (v1, v2) => {
-  return semver.gte(
-    semver.coerce(v1).version,
-    semver.coerce(v2).version,
-  )
-}
diff --git a/packages/@uppy/companion/src/server/middlewares.js b/packages/@uppy/companion/src/server/middlewares.js
index c344ff1602c..7c9cf93cc1a 100644
--- a/packages/@uppy/companion/src/server/middlewares.js
+++ b/packages/@uppy/companion/src/server/middlewares.js
@@ -123,13 +123,13 @@ exports.cors = (options = {}) => (req, res, next) => {
   const exposeHeadersSet = new Set(existingExposeHeaders?.split(',')?.map((method) => method.trim().toLowerCase()))
 
   // exposed so it can be accessed for our custom uppy client preflight
-  exposeHeadersSet.add('access-control-allow-headers')
+  exposeHeadersSet.add('access-control-allow-headers') // todo remove in next major, see https://github.com/transloadit/uppy/pull/4462
   if (options.sendSelfEndpoint) exposeHeadersSet.add('i-am')
 
   // Needed for basic operation: https://github.com/transloadit/uppy/issues/3021
   const allowedHeaders = [
     'uppy-auth-token',
-    'uppy-versions',
+    'uppy-versions', // todo remove in the future? see https://github.com/transloadit/uppy/pull/4462
     'uppy-credentials-params',
     'authorization',
     'origin',
@@ -191,18 +191,12 @@ exports.getCompanionMiddleware = (options) => {
    * @param {Function} next
    */
   const middleware = (req, res, next) => {
-    const versionFromQuery = req.query.uppyVersions ? decodeURIComponent(req.query.uppyVersions) : null
     req.companion = {
       options,
       s3Client: getS3Client(options),
       authToken: req.header('uppy-auth-token') || req.query.uppyAuthToken,
-      clientVersion: req.header('uppy-versions') || versionFromQuery || '1.0.0',
       buildURL: getURLBuilder(options),
     }
-
-    if (options.logClientVersion) {
-      logger.info(`uppy client version ${req.companion.clientVersion}`, 'companion.client.version')
-    }
     next()
   }
 
diff --git a/packages/@uppy/companion/test/__tests__/callback.js b/packages/@uppy/companion/test/__tests__/callback.js
index 4eee609aa10..2ab5a689794 100644
--- a/packages/@uppy/companion/test/__tests__/callback.js
+++ b/packages/@uppy/companion/test/__tests__/callback.js
@@ -43,7 +43,7 @@ describe('test authentication callback', () => {
   test('the token gets sent via html', () => {
     // see mock ../../src/server/helpers/oauth-state above for state values
     return request(authServer)
-      .get(`/dropbox/send-token?uppyAuthToken=${token}&state=state-with-newer-version`)
+      .get(`/dropbox/send-token?uppyAuthToken=${token}`)
       .expect(200)
       .expect((res) => {
         const body = `
diff --git a/packages/@uppy/companion/test/mockoauthstate.js b/packages/@uppy/companion/test/mockoauthstate.js
index 63fe9d8b83e..8a7db59057b 100644
--- a/packages/@uppy/companion/test/mockoauthstate.js
+++ b/packages/@uppy/companion/test/mockoauthstate.js
@@ -2,23 +2,11 @@ module.exports = () => {
   return {
     generateState: () => 'some-cool-nice-encrytpion',
     addToState: () => 'some-cool-nice-encrytpion',
-    getFromState: (state, key) => {
+    getFromState: (state) => {
       if (state === 'state-with-invalid-instance-url') {
         return 'http://localhost:3452'
       }
 
-      if (state === 'state-with-older-version' && key === 'clientVersion') {
-        return '@uppy/companion-client=1.0.1'
-      }
-
-      if (state === 'state-with-newer-version' && key === 'clientVersion') {
-        return '@uppy/companion-client=1.0.3'
-      }
-
-      if (state === 'state-with-newer-version-old-style' && key === 'clientVersion') {
-        return 'companion-client:1.0.2'
-      }
-
       return 'http://localhost:3020'
     },
   }
diff --git a/packages/@uppy/core/src/Restricter.ts b/packages/@uppy/core/src/Restricter.ts
index 07eafd64458..3d75cd741b0 100644
--- a/packages/@uppy/core/src/Restricter.ts
+++ b/packages/@uppy/core/src/Restricter.ts
@@ -1,7 +1,5 @@
 /* eslint-disable max-classes-per-file, class-methods-use-this */
-// @ts-expect-error untyped
 import prettierBytes from '@transloadit/prettier-bytes'
-// @ts-expect-error untyped
 import match from 'mime-match'
 import Translator from '@uppy/utils/lib/Translator'
 import type { Body, Meta, UppyFile } from '@uppy/utils/lib/UppyFile'
diff --git a/packages/@uppy/core/src/UIPlugin.ts b/packages/@uppy/core/src/UIPlugin.ts
index d7f0a5fe44c..338d8ecfc38 100644
--- a/packages/@uppy/core/src/UIPlugin.ts
+++ b/packages/@uppy/core/src/UIPlugin.ts
@@ -163,6 +163,7 @@ class UIPlugin<
    * This is the case with @uppy/react plugins, for example.
    */
   render(state: Record<string, unknown>): ComponentChild {
+    // eslint-disable-line @typescript-eslint/no-unused-vars
     throw new Error(
       'Extend the render method to add your plugin to a DOM element',
     )
diff --git a/packages/@uppy/core/src/Uppy.test.ts b/packages/@uppy/core/src/Uppy.test.ts
index 85495f498e1..f9bbb6b0775 100644
--- a/packages/@uppy/core/src/Uppy.test.ts
+++ b/packages/@uppy/core/src/Uppy.test.ts
@@ -516,7 +516,7 @@ describe('src/Core', () => {
   describe('preprocessors', () => {
     it('should add and remove preprocessor', () => {
       const core = new Core()
-      const preprocessor = () => {}
+      const preprocessor = Function.prototype
       expect(core.removePreProcessor(preprocessor)).toBe(false)
       core.addPreProcessor(preprocessor)
       expect(core.removePreProcessor(preprocessor)).toBe(true)
@@ -635,7 +635,7 @@ describe('src/Core', () => {
   describe('postprocessors', () => {
     it('should add and remove postprocessor', () => {
       const core = new Core()
-      const postprocessor = () => {}
+      const postprocessor = Function.prototype
       expect(core.removePostProcessor(postprocessor)).toBe(false)
       core.addPostProcessor(postprocessor)
       expect(core.removePostProcessor(postprocessor)).toBe(true)
@@ -752,7 +752,7 @@ describe('src/Core', () => {
   describe('uploaders', () => {
     it('should add and remove uploader', () => {
       const core = new Core()
-      const uploader = () => {}
+      const uploader = Function.prototype
       expect(core.removeUploader(uploader)).toBe(false)
       core.addUploader(uploader)
       expect(core.removeUploader(uploader)).toBe(true)
@@ -1326,9 +1326,9 @@ describe('src/Core', () => {
   })
 
   describe('restoring a file', () => {
-    it.skip('should restore a file', () => {})
+    it.skip('should restore a file')
 
-    it.skip("should fail to restore a file if it doesn't exist", () => {})
+    it.skip("should fail to restore a file if it doesn't exist")
   })
 
   describe('get a file', () => {
@@ -1861,7 +1861,7 @@ describe('src/Core', () => {
       }).not.toThrowError()
     })
 
-    it.skip('should enforce the minNumberOfFiles rule', () => {})
+    it.skip('should enforce the minNumberOfFiles rule')
 
     it('should enforce the allowedFileTypes rule', () => {
       const core = new Core({
@@ -2291,6 +2291,8 @@ describe('src/Core', () => {
         data: new File([sampleImage], { type: 'image/jpeg' }),
       })
 
+      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+      // @ts-ignore accessing private field
       core[Symbol.for('uppy test: createUpload')](
         Object.keys(core.getState().files),
       )
@@ -2312,6 +2314,7 @@ describe('src/Core', () => {
           strings: {
             test: 'beep boop',
           },
+          pluralize: () => 0,
         },
       })
 
diff --git a/packages/@uppy/core/src/Uppy.ts b/packages/@uppy/core/src/Uppy.ts
index 08a760ee33d..e5240327ddb 100644
--- a/packages/@uppy/core/src/Uppy.ts
+++ b/packages/@uppy/core/src/Uppy.ts
@@ -327,7 +327,7 @@ export class Uppy<M extends Meta, B extends Body> {
 
     // Exposing uppy object on window for debugging and testing
     if (this.opts.debug && typeof window !== 'undefined') {
-      // @ts-expect-error string as index type is fine
+      // @ts-expect-error fine
       window[this.opts.id] = this
     }
 
@@ -807,11 +807,10 @@ export class Uppy<M extends Meta, B extends Body> {
 
         // If a file has been recovered (Golden Retriever), but we were unable to recover its data (probably too large),
         // users are asked to re-select these half-recovered files and then this method will be called again.
-        // In order to keep the progress, meta and everthing else, we keep the existing file,
+        // In order to keep the progress, meta and everything else, we keep the existing file,
         // but we replace `data`, and we remove `isGhost`, because the file is no longer a ghost now
         const isGhost = existingFiles[newFile.id]?.isGhost
         if (isGhost) {
-          // eslint-disable-next-line @typescript-eslint/no-unused-vars
           const existingFileState = existingFiles[newFile.id]
           newFile = {
             ...existingFileState,
@@ -1338,7 +1337,7 @@ export class Uppy<M extends Meta, B extends Body> {
       if (typeof error === 'object' && error.message) {
         this.log(error.message, 'error')
         const newError = new Error(
-          this.i18n('failedToUpload', { file: file?.name }),
+          this.i18n('failedToUpload', { file: file?.name ?? '' }),
         ) as any // we may want a new custom error here
         newError.isUserFacing = true // todo maybe don't do this with all errors?
         newError.details = error.message
@@ -1624,7 +1623,9 @@ export class Uppy<M extends Meta, B extends Body> {
     return undefined
   }
 
-  [Symbol.for('uppy test: getPlugins')](type: string): UnknownPlugin<M, B>[] {
+  private [Symbol.for('uppy test: getPlugins')](
+    type: string,
+  ): UnknownPlugin<M, B>[] {
     return this.#plugins[type]
   }
 
@@ -1799,9 +1800,9 @@ export class Uppy<M extends Meta, B extends Body> {
     return uploadID
   }
 
-  // @ts-expect-error same type as createUpload
-  [Symbol.for('uppy test: createUpload')](...args): string {
-    // @ts-expect-error same type as createUpload
+  // @ts-expect-error same as createUpload
+  private [Symbol.for('uppy test: createUpload')](...args): string {
+    // @ts-expect-error https://github.com/microsoft/TypeScript/issues/47595
     return this.#createUpload(...args)
   }
 
diff --git a/packages/@uppy/core/src/locale.ts b/packages/@uppy/core/src/locale.ts
index 16a18cf3a46..92674805d65 100644
--- a/packages/@uppy/core/src/locale.ts
+++ b/packages/@uppy/core/src/locale.ts
@@ -58,6 +58,7 @@ export default {
       0: 'Added %{smart_count} file from %{folder}',
       1: 'Added %{smart_count} files from %{folder}',
     },
-    additionalRestrictionsFailed: '%{count} additional restrictions were not fulfilled',
+    additionalRestrictionsFailed:
+      '%{count} additional restrictions were not fulfilled',
   },
 }
diff --git a/packages/@uppy/core/src/mocks/acquirerPlugin1.ts b/packages/@uppy/core/src/mocks/acquirerPlugin1.ts
index 5b08d2b1adf..5fc46ba2f36 100644
--- a/packages/@uppy/core/src/mocks/acquirerPlugin1.ts
+++ b/packages/@uppy/core/src/mocks/acquirerPlugin1.ts
@@ -1,8 +1,8 @@
 import { vi } from 'vitest' // eslint-disable-line import/no-extraneous-dependencies
 import UIPlugin from '../UIPlugin.ts'
 
-export default class TestSelector1 extends UIPlugin {
-  constructor (uppy, opts) {
+export default class TestSelector1 extends UIPlugin<any, any, any> {
+  constructor(uppy, opts) {
     super(uppy, opts)
     this.type = 'acquirer'
     this.id = 'TestSelector1'
@@ -15,7 +15,7 @@ export default class TestSelector1 extends UIPlugin {
     }
   }
 
-  run (results) {
+  run(results) {
     this.uppy.log({
       class: this.constructor.name,
       method: 'run',
@@ -25,11 +25,11 @@ export default class TestSelector1 extends UIPlugin {
     return Promise.resolve('success')
   }
 
-  update (state) {
+  update(state) {
     this.mocks.update(state)
   }
 
-  uninstall () {
+  uninstall() {
     this.mocks.uninstall()
   }
 }
diff --git a/packages/@uppy/core/src/mocks/acquirerPlugin2.ts b/packages/@uppy/core/src/mocks/acquirerPlugin2.ts
index 42da1f378c9..15e499c0bd1 100644
--- a/packages/@uppy/core/src/mocks/acquirerPlugin2.ts
+++ b/packages/@uppy/core/src/mocks/acquirerPlugin2.ts
@@ -1,8 +1,8 @@
 import { vi } from 'vitest' // eslint-disable-line import/no-extraneous-dependencies
 import UIPlugin from '../UIPlugin.ts'
 
-export default class TestSelector2 extends UIPlugin {
-  constructor (uppy, opts) {
+export default class TestSelector2 extends UIPlugin<any, any, any> {
+  constructor(uppy, opts) {
     super(uppy, opts)
     this.type = 'acquirer'
     this.id = 'TestSelector2'
@@ -15,7 +15,7 @@ export default class TestSelector2 extends UIPlugin {
     }
   }
 
-  run (results) {
+  run(results) {
     this.uppy.log({
       class: this.constructor.name,
       method: 'run',
@@ -25,11 +25,11 @@ export default class TestSelector2 extends UIPlugin {
     return Promise.resolve('success')
   }
 
-  update (state) {
+  update(state) {
     this.mocks.update(state)
   }
 
-  uninstall () {
+  uninstall() {
     this.mocks.uninstall()
   }
 }
diff --git a/packages/@uppy/core/src/mocks/invalidPluginWithoutId.ts b/packages/@uppy/core/src/mocks/invalidPluginWithoutId.ts
index 6d4fcf3dde8..93fe3e4cc74 100644
--- a/packages/@uppy/core/src/mocks/invalidPluginWithoutId.ts
+++ b/packages/@uppy/core/src/mocks/invalidPluginWithoutId.ts
@@ -1,13 +1,17 @@
 import UIPlugin from '../UIPlugin.ts'
 
-export default class InvalidPluginWithoutName extends UIPlugin {
-  constructor (uppy, opts) {
+export default class InvalidPluginWithoutName extends UIPlugin<any, any, any> {
+  public type: string
+
+  public name: string
+
+  constructor(uppy, opts) {
     super(uppy, opts)
     this.type = 'acquirer'
     this.name = this.constructor.name
   }
 
-  run (results) {
+  run(results) {
     this.uppy.log({
       class: this.constructor.name,
       method: 'run',
diff --git a/packages/@uppy/core/src/mocks/invalidPluginWithoutType.ts b/packages/@uppy/core/src/mocks/invalidPluginWithoutType.ts
index 2a2cbfaa248..96ebad2c8cc 100644
--- a/packages/@uppy/core/src/mocks/invalidPluginWithoutType.ts
+++ b/packages/@uppy/core/src/mocks/invalidPluginWithoutType.ts
@@ -1,13 +1,17 @@
 import UIPlugin from '../UIPlugin.ts'
 
-export default class InvalidPluginWithoutType extends UIPlugin {
-  constructor (uppy, opts) {
+export default class InvalidPluginWithoutType extends UIPlugin<any, any, any> {
+  public id: string
+
+  public name: string
+
+  constructor(uppy, opts) {
     super(uppy, opts)
     this.id = 'InvalidPluginWithoutType'
     this.name = this.constructor.name
   }
 
-  run (results) {
+  run(results) {
     this.uppy.log({
       class: this.constructor.name,
       method: 'run',
diff --git a/packages/@uppy/core/src/supportsUploadProgress.test.ts b/packages/@uppy/core/src/supportsUploadProgress.test.ts
index 9586f4ef239..6dc2f8f478c 100644
--- a/packages/@uppy/core/src/supportsUploadProgress.test.ts
+++ b/packages/@uppy/core/src/supportsUploadProgress.test.ts
@@ -4,26 +4,54 @@ import supportsUploadProgress from './supportsUploadProgress.ts'
 describe('supportsUploadProgress', () => {
   it('returns true in working browsers', () => {
     // Firefox 64 (dev edition)
-    expect(supportsUploadProgress('Mozilla/5.0 (X11; Linux x86_64; rv:64.0) Gecko/20100101 Firefox/64.0')).toBe(true)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (X11; Linux x86_64; rv:64.0) Gecko/20100101 Firefox/64.0',
+      ),
+    ).toBe(true)
 
     // Chromium 70
-    expect(supportsUploadProgress('Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36')).toBe(true)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36',
+      ),
+    ).toBe(true)
 
     // IE 11
-    expect(supportsUploadProgress('Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; rv:11.0) like Gecko')).toBe(true)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; rv:11.0) like Gecko',
+      ),
+    ).toBe(true)
 
     // MS Edge 14
-    expect(supportsUploadProgress('Chrome (AppleWebKit/537.1; Chrome50.0; Windows NT 6.3) AppleWebKit/537.36 (KHTML like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393')).toBe(true)
+    expect(
+      supportsUploadProgress(
+        'Chrome (AppleWebKit/537.1; Chrome50.0; Windows NT 6.3) AppleWebKit/537.36 (KHTML like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393',
+      ),
+    ).toBe(true)
 
     // MS Edge 18, supposedly fixed
-    expect(supportsUploadProgress('Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/18.18218')).toBe(true)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/18.18218',
+      ),
+    ).toBe(true)
   })
 
   it('returns false in broken browsers', () => {
     // MS Edge 15, first broken version
-    expect(supportsUploadProgress('Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/15.15063')).toBe(false)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/15.15063',
+      ),
+    ).toBe(false)
 
     // MS Edge 17
-    expect(supportsUploadProgress('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/17.17134')).toBe(false)
+    expect(
+      supportsUploadProgress(
+        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/17.17134',
+      ),
+    ).toBe(false)
   })
 })
diff --git a/packages/@uppy/provider-views/src/ProviderView/ProviderView.jsx b/packages/@uppy/provider-views/src/ProviderView/ProviderView.jsx
index 517854347c2..314ee6bd101 100644
--- a/packages/@uppy/provider-views/src/ProviderView/ProviderView.jsx
+++ b/packages/@uppy/provider-views/src/ProviderView/ProviderView.jsx
@@ -242,9 +242,8 @@ export default class ProviderView extends View {
   }
 
   async handleAuth () {
-    const clientVersion = `@uppy/provider-views=${ProviderView.VERSION}`
     try {
-      await this.provider.login({ uppyVersions: clientVersion })
+      await this.provider.login()
       this.plugin.setPluginState({ authenticated: true })
       this.preFirstRender()
     } catch (e) {
diff --git a/packages/@uppy/utils/src/Translator.ts b/packages/@uppy/utils/src/Translator.ts
index 7435559d9a4..f882f96726b 100644
--- a/packages/@uppy/utils/src/Translator.ts
+++ b/packages/@uppy/utils/src/Translator.ts
@@ -7,9 +7,7 @@ export interface Locale<T extends number = number> {
 }
 
 export type OptionalPluralizeLocale<T extends number = number> =
-  | (Omit<Locale<T>, 'pluralize'> & {
-      pluralize?: (n: number) => T
-    })
+  | (Omit<Locale<T>, 'pluralize'> & Partial<Pick<Locale<T>, 'pluralize'>>)
   | undefined
 
 // eslint-disable-next-line no-use-before-define
@@ -18,7 +16,7 @@ export type I18n = Translator['translate']
 type Options = {
   smart_count?: number
 } & {
-  [key: string]: string | number | undefined
+  [key: string]: string | number
 }
 
 function insertReplacement(
diff --git a/packages/@uppy/utils/src/emitSocketProgress.ts b/packages/@uppy/utils/src/emitSocketProgress.ts
index fa3c0a242ea..4b1e26e5f83 100644
--- a/packages/@uppy/utils/src/emitSocketProgress.ts
+++ b/packages/@uppy/utils/src/emitSocketProgress.ts
@@ -5,7 +5,7 @@ import type { FileProgress } from './FileProgress'
 function emitSocketProgress(
   uploader: any,
   progressData: FileProgress,
-  file: UppyFile<any,any>,
+  file: UppyFile<any, any>,
 ): void {
   const { progress, bytesUploaded, bytesTotal } = progressData
   if (progress) {
diff --git a/packages/@uppy/utils/src/fileFilters.ts b/packages/@uppy/utils/src/fileFilters.ts
index 4b12936aba7..cdd67a74890 100644
--- a/packages/@uppy/utils/src/fileFilters.ts
+++ b/packages/@uppy/utils/src/fileFilters.ts
@@ -1,13 +1,18 @@
 import type { UppyFile } from './UppyFile'
 
-export function filterNonFailedFiles(files: UppyFile<any,any>[]): UppyFile<any,any>[] {
-  const hasError = (file: UppyFile<any,any>): boolean => 'error' in file && !!file.error
+export function filterNonFailedFiles(
+  files: UppyFile<any, any>[],
+): UppyFile<any, any>[] {
+  const hasError = (file: UppyFile<any, any>): boolean =>
+    'error' in file && !!file.error
 
   return files.filter((file) => !hasError(file))
 }
 
 // Don't double-emit upload-started for Golden Retriever-restored files that were already started
-export function filterFilesToEmitUploadStarted(files: UppyFile<any,any>[]): UppyFile<any,any>[] {
+export function filterFilesToEmitUploadStarted(
+  files: UppyFile<any, any>[],
+): UppyFile<any, any>[] {
   return files.filter(
     (file) => !file.progress?.uploadStarted || !file.isRestored,
   )
diff --git a/packages/@uppy/utils/src/findDOMElement.ts b/packages/@uppy/utils/src/findDOMElement.ts
index 258153694fa..5282c61b44b 100644
--- a/packages/@uppy/utils/src/findDOMElement.ts
+++ b/packages/@uppy/utils/src/findDOMElement.ts
@@ -4,9 +4,9 @@ import isDOMElement from './isDOMElement.ts'
  * Find a DOM element.
  */
 export default function findDOMElement(
-  element: HTMLElement | string,
+  element: Node | string,
   context = document,
-): HTMLElement | null {
+): Element | null {
   if (typeof element === 'string') {
     return context.querySelector(element)
   }
diff --git a/packages/@uppy/utils/src/generateFileID.ts b/packages/@uppy/utils/src/generateFileID.ts
index 17f3867fd97..aa41667e7dc 100644
--- a/packages/@uppy/utils/src/generateFileID.ts
+++ b/packages/@uppy/utils/src/generateFileID.ts
@@ -19,7 +19,7 @@ function encodeFilename(name: string): string {
  * Takes a file object and turns it into fileID, by converting file.name to lowercase,
  * removing extra characters and adding type, size and lastModified
  */
-export default function generateFileID(file: UppyFile<any,any>): string {
+export default function generateFileID(file: UppyFile<any, any>): string {
   // It's tempting to do `[items].filter(Boolean).join('-')` here, but that
   // is slower! simple string concatenation is fast
 
@@ -48,7 +48,7 @@ export default function generateFileID(file: UppyFile<any,any>): string {
 
 // If the provider has a stable, unique ID, then we can use that to identify the file.
 // Then we don't have to generate our own ID, and we can add the same file many times if needed (different path)
-function hasFileStableId(file: UppyFile<any,any>): boolean {
+function hasFileStableId(file: UppyFile<any, any>): boolean {
   if (!file.isRemote || !file.remote) return false
   // These are the providers that it seems like have stable IDs for their files. The other's I haven't checked yet.
   const stableIdProviders = new Set([
@@ -61,7 +61,7 @@ function hasFileStableId(file: UppyFile<any,any>): boolean {
   return stableIdProviders.has(file.remote.provider as any)
 }
 
-export function getSafeFileId(file: UppyFile<any,any>): string {
+export function getSafeFileId(file: UppyFile<any, any>): string {
   if (hasFileStableId(file)) return file.id
 
   const fileType = getFileType(file)
diff --git a/packages/@uppy/utils/src/getFileType.test.ts b/packages/@uppy/utils/src/getFileType.test.ts
index aa0175bccd8..2316961b218 100644
--- a/packages/@uppy/utils/src/getFileType.test.ts
+++ b/packages/@uppy/utils/src/getFileType.test.ts
@@ -8,7 +8,7 @@ describe('getFileType', () => {
       isRemote: true,
       type: 'audio/webm',
       name: 'foo.webm',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     expect(getFileType(file)).toEqual('audio/webm')
   })
 
@@ -17,7 +17,7 @@ describe('getFileType', () => {
       type: 'audio/webm',
       name: 'foo.webm',
       data: 'sdfsdfhq9efbicw',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     expect(getFileType(file)).toEqual('audio/webm')
   })
 
@@ -25,24 +25,24 @@ describe('getFileType', () => {
     const fileMP3 = {
       name: 'foo.mp3',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     const fileYAML = {
       name: 'bar.yaml',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     const fileMKV = {
       name: 'bar.mkv',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     const fileDicom = {
       name: 'bar.dicom',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     const fileWebp = {
       name: 'bar.webp',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
-    const toUpper = (file: UppyFile<any,any>) => ({
+    } as any as UppyFile<any, any>
+    const toUpper = (file: UppyFile<any, any>) => ({
       ...file,
       name: file.name.toUpperCase(),
     })
@@ -62,7 +62,7 @@ describe('getFileType', () => {
     const file = {
       name: 'foobar',
       data: 'sdfsfhfh329fhwihs',
-    } as any as UppyFile<any,any>
+    } as any as UppyFile<any, any>
     expect(getFileType(file)).toEqual('application/octet-stream')
   })
 })
diff --git a/private/js2ts/index.mjs b/private/js2ts/index.mjs
index 1acb74ab3e3..92f10c63e1a 100755
--- a/private/js2ts/index.mjs
+++ b/private/js2ts/index.mjs
@@ -7,7 +7,7 @@
 
 import { opendir, readFile, open, writeFile, rm } from 'node:fs/promises'
 import { argv } from 'node:process'
-import { extname } from 'node:path'
+import { basename, extname, join } from 'node:path'
 import { existsSync } from 'node:fs'
 
 const packageRoot = new URL(`../../packages/${argv[2]}/`, import.meta.url)
@@ -58,12 +58,16 @@ try {
 
 for await (const dirent of dir) {
   if (!dirent.isDirectory()) {
-    const { path: filepath } = dirent
-    const ext = extname(filepath)
+    const { name } = dirent
+    const ext = extname(name)
     if (ext !== '.js' && ext !== '.jsx') continue // eslint-disable-line no-continue
+    const filePath =
+      basename(dirent.path) === name
+        ? dirent.path // Some versions of Node.js give the full path as dirent.path.
+        : join(dirent.path, name) // Others supply only the path to the parent.
     await writeFile(
-      filepath.slice(0, -ext.length) + ext.replace('js', 'ts'),
-      (await readFile(filepath, 'utf-8'))
+      `${filePath.slice(0, -ext.length)}${ext.replace('js', 'ts')}`,
+      (await readFile(filePath, 'utf-8'))
         .replace(
           // The following regex aims to capture all imports and reexports of local .js(x) files to replace it to .ts(x)
           // It's far from perfect and will have false positives and false negatives.
@@ -78,7 +82,7 @@ for await (const dirent of dir) {
             `// @ts-ignore We don't want TS to generate types for the package.json${originalImport}`,
         ),
     )
-    await rm(filepath)
+    await rm(filePath)
   }
 }
 
diff --git a/yarn.lock b/yarn.lock
index 9c4cf782bc4..66bb7bd31be 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -9332,7 +9332,6 @@ __metadata:
     node-schedule: 2.1.0
     prom-client: 14.0.1
     redis: 4.2.0
-    semver: 7.5.3
     serialize-error: ^2.1.0
     serialize-javascript: ^6.0.0
     supertest: 6.2.4