[Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v3.0.0...v4.0.0-rc.1) BREAKING CHANGES * The js-sdk node module now exports ES6 rather than ES5. If you wish to supports target that aren't compatible with ES6, you will need to transpile the js-sdk to a suitable dialect. All Changes * Convert secret storage to new account data API [\#1154](https://github.com/matrix-org/matrix-js-sdk/pull/1154) * Add v5 as a safe room version [\#1157](https://github.com/matrix-org/matrix-js-sdk/pull/1157) * Add API to get account data from server [\#1153](https://github.com/matrix-org/matrix-js-sdk/pull/1153) * Fix sourcemaps by refactoring the build system [\#1151](https://github.com/matrix-org/matrix-js-sdk/pull/1151) * record, report, and notify about olm errors [\#1146](https://github.com/matrix-org/matrix-js-sdk/pull/1146) * Send device messages for the same user in same API call. [\#1148](https://github.com/matrix-org/matrix-js-sdk/pull/1148) * Add an option to ignore unverified devices [\#1150](https://github.com/matrix-org/matrix-js-sdk/pull/1150) * Sign key backup with cross-signing key on upgrade [\#1144](https://github.com/matrix-org/matrix-js-sdk/pull/1144) * Emoji verification: Change name of 🔒 to lock [\#1145](https://github.com/matrix-org/matrix-js-sdk/pull/1145) * use a separate object for each encrypted content [\#1147](https://github.com/matrix-org/matrix-js-sdk/pull/1147) * Sourcemaps: develop -> feature branch [\#1143](https://github.com/matrix-org/matrix-js-sdk/pull/1143) * Use a safer import/export scheme for the ContentRepo utilities [\#1134](https://github.com/matrix-org/matrix-js-sdk/pull/1134) * Fix error handling in decryptGroupMessage [\#1142](https://github.com/matrix-org/matrix-js-sdk/pull/1142) * Add additional properties to package.json for riot-web's webpack [\#1131](https://github.com/matrix-org/matrix-js-sdk/pull/1131) * Fix import for indexeddb crypto store [\#1133](https://github.com/matrix-org/matrix-js-sdk/pull/1133) * Use the right request when creating clients [\#1132](https://github.com/matrix-org/matrix-js-sdk/pull/1132) * Target NodeJS 10, minified browser bundle, and other publishing/package things [\#1127](https://github.com/matrix-org/matrix-js-sdk/pull/1127) * Re-focus sourcemap generation [\#1126](https://github.com/matrix-org/matrix-js-sdk/pull/1126) * Remove ancient polyfill for prototype inheritance [\#1125](https://github.com/matrix-org/matrix-js-sdk/pull/1125) * Remove "source-map-support" from tests because it makes sourcemaps worse [\#1124](https://github.com/matrix-org/matrix-js-sdk/pull/1124) * Remove ancient "use strict" annotations [\#1123](https://github.com/matrix-org/matrix-js-sdk/pull/1123) * Use ES6 imports/exports instead of older CommonJS ones [\#1122](https://github.com/matrix-org/matrix-js-sdk/pull/1122) * [BREAKING] Refactor the entire build process [\#1113](https://github.com/matrix-org/matrix-js-sdk/pull/1113)