# Cypress v4.1.0 — Release & Upgrade Intelligence
- **Product:** Cypress (https://www.cypress.io)
- **Version:** v4.1.0
- **Released:** Feb 28, 2020
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/cypress/updates/v4.1.0/

## Executive Summary (TL;DR)
Cypress v4.1.0. Source highlight: *Released 2/28/2020*

## Bug Fixes
- Fixed a regression where Cypress could throw a "Maximum call stack size exceeded" error when transmitting a circular object over the internal WebSocket. Fixes #6582.
- We fixed an issue where using Chromium-family browsers could cause Cypress to throw a "WebSocket is not open: readyState 3" error under certain conditions. Fixes #5685.
- We now more thoroughly ensure the parent of an element exists when recursively calling visibility and existence checks in order to prevent some maximum call stack errors. Fixes #4373.
- We fixed an issue where a maximum call stack error would throw in some circumstances when `xhr.onreadystatechange` is accessed. Fixes #5864.
- We fixed a regression in 3.5.0 where typing into an iframe with a body element with the contenteditable attribute would throw an error. Fixes #5930.
- We now set the default window size when running Chrome headlessly to 1280x720. Fixes #6210.