# Deno v1.4.0 — Release & Upgrade Intelligence
- **Product:** Deno (https://deno.com)
- **Version:** v1.4.0
- **Released:** Sep 13, 2020
- **Impact Score:** 7/10
- **Breaking Changes:** Source flagged
- **Canonical Analysis:** https://changelogs.us/deno/updates/v1.4.0/

## Executive Summary (TL;DR)
Deno v1.4.0. Source highlight: feat: Implement WebSocket API (#7051, #7437)

## Breaking Changes & Deprecations
- - BREAKING(std/fs): remove writeJson and writeJsonSync (#7256)
- - BREAKING(std/fs): remove readJson and readJsonSync (#7255)
- - BREAKING(std/ws): remove connect method (#7403)

## New Features
- feat: Implement WebSocket API (#7051, #7437)
- feat(console): print proxy details (#7139)
- feat(console): support CSS styling with "%c" (#7357)
- feat(core): Add JSON ops (#7336)
- feat(fmt, lint): show number of checked files (#7312)
- feat(info): Dependency count and sizes (#6786, #7439)

## Improvements
- refactor: Improve placeholder module names (#7430)
- refactor: improve tsc diagnostics (#7420)

## Bug Fixes
- fix: Empty Response body returns 0-byte array (#7387)
- fix: panic on process.kill() after run (#7405)
- fix: colors mismatch (#7367)
- fix: compiler config resolution using relative paths (#7392)
- fix(core): panic on big string allocation (#7395)
- fix(op_crates/web): Use "deno:" URLs for internal script specifiers (#7383)