diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5797356c..f0c74d635 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,25 @@
 # Embroider Changelog
 
+## v0.43.0 (2021-07-13)
+
+#### :boom: Breaking Change
+* `macros`
+  * [#888](https://github.com/embroider-build/embroider/pull/888) Expose sourceOfConfig to macro config mergers ([@mydea](https://github.com/mydea))
+* `babel-loader-7`, `compat`, `core`, `macros`, `shared-internals`, `webpack`
+  * [#890](https://github.com/embroider-build/embroider/pull/890) Drop support for apps that use babel 6 ([@ef4](https://github.com/ef4))
+
+#### :bug: Bug Fix
+* `macros`
+  * [#886](https://github.com/embroider-build/embroider/pull/886) `undefined` does not serialize with broccoli-babel-transpiler ([@thoov](https://github.com/thoov))
+* `core`, `shared-internals`, `webpack`
+  * [#881](https://github.com/embroider-build/embroider/pull/881) Fix race condition finding the owning package of a given file when using multiple workers ([@ef4](https://github.com/ef4))
+
+#### Committers: 3
+- Edward Faulkner ([@ef4](https://github.com/ef4))
+- Francesco Novy ([@mydea](https://github.com/mydea))
+- Travis Hoover ([@thoov](https://github.com/thoov))
+
+
 ## v0.42.3 (2021-06-28)
 
 #### :rocket: Enhancement
diff --git a/package.json b/package.json
index fc00a2f44..5f7d09b81 100644
--- a/package.json
+++ b/package.json
@@ -89,5 +89,5 @@
     "node": "12.16.1",
     "yarn": "1.22.5"
   },
-  "version": "0.42.3"
+  "version": "0.43.0"
 }
diff --git a/packages/addon-shim/package.json b/packages/addon-shim/package.json
index 2b2b7b37c..c92af6f3b 100644
--- a/packages/addon-shim/package.json
+++ b/packages/addon-shim/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/addon-shim",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "description": "Make v2 addons work in non-Embroider apps.",
   "keywords": [
     "ember-addon"
@@ -21,7 +21,7 @@
     "prepare": "tsc"
   },
   "dependencies": {
-    "@embroider/shared-internals": "^0.42.3",
+    "@embroider/shared-internals": "^0.43.0",
     "ember-auto-import": "^2.0.1",
     "semver": "^7.3.5"
   },
diff --git a/packages/babel-loader-8/package.json b/packages/babel-loader-8/package.json
index 0cb07cfcf..43bd28faa 100644
--- a/packages/babel-loader-8/package.json
+++ b/packages/babel-loader-8/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/babel-loader-8",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "repository": {
     "type": "git",
     "url": "https://github.com/embroider-build/embroider.git",
@@ -12,7 +12,7 @@
     "@babel/core": "^7.14.5",
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.14.5",
     "@babel/plugin-proposal-optional-chaining": "^7.14.5",
-    "@embroider/core": "0.42.3",
+    "@embroider/core": "0.43.0",
     "babel-loader": "8"
   },
   "engines": {
diff --git a/packages/compat/package.json b/packages/compat/package.json
index 295194da2..eebb50690 100644
--- a/packages/compat/package.json
+++ b/packages/compat/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/compat",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "Backward compatibility layer for the Embroider build system.",
   "repository": {
@@ -30,8 +30,8 @@
     "@babel/preset-env": "^7.14.5",
     "@babel/traverse": "^7.14.5",
     "@babel/types": "^7.14.5",
-    "@embroider/macros": "0.42.3",
-    "@embroider/shared-internals": "0.42.3",
+    "@embroider/macros": "0.43.0",
+    "@embroider/shared-internals": "0.43.0",
     "@types/babel__code-frame": "^7.0.2",
     "@types/yargs": "^17.0.0",
     "assert-never": "^1.1.0",
@@ -84,7 +84,7 @@
     "typescript": "~4.0.0"
   },
   "peerDependencies": {
-    "@embroider/core": "0.42.3"
+    "@embroider/core": "0.43.0"
   },
   "engines": {
     "node": "12.* || 14.* || >= 16"
diff --git a/packages/core/package.json b/packages/core/package.json
index 2d60d0d49..d0a29ac5d 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/core",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "A build system for EmberJS applications.",
   "repository": {
@@ -38,8 +38,8 @@
     "@babel/runtime": "^7.14.5",
     "@babel/traverse": "^7.14.5",
     "@babel/types": "^7.14.5",
-    "@embroider/macros": "0.42.3",
-    "@embroider/shared-internals": "0.42.3",
+    "@embroider/macros": "0.43.0",
+    "@embroider/shared-internals": "0.43.0",
     "assert-never": "^1.2.1",
     "broccoli-node-api": "^1.7.0",
     "broccoli-persistent-filter": "^3.1.2",
diff --git a/packages/hbs-loader/package.json b/packages/hbs-loader/package.json
index b27e34c2d..074bbe191 100644
--- a/packages/hbs-loader/package.json
+++ b/packages/hbs-loader/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/hbs-loader",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "Glimmer handlebars loader for webpack",
   "repository": {
@@ -28,7 +28,7 @@
     "typescript": "~4.0.0"
   },
   "peerDependencies": {
-    "@embroider/core": "0.42.3",
+    "@embroider/core": "0.43.0",
     "webpack": "^4 || ^5"
   },
   "engines": {
diff --git a/packages/macros/package.json b/packages/macros/package.json
index aa039c63d..79b45be9f 100644
--- a/packages/macros/package.json
+++ b/packages/macros/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/macros",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "Standardized build-time macros for ember apps.",
   "keywords": [
@@ -24,7 +24,7 @@
     "test": "jest"
   },
   "dependencies": {
-    "@embroider/shared-internals": "0.42.3",
+    "@embroider/shared-internals": "0.43.0",
     "assert-never": "^1.2.1",
     "ember-cli-babel": "^7.26.6",
     "lodash": "^4.17.21",
@@ -35,7 +35,7 @@
     "@babel/core": "^7.14.5",
     "@babel/traverse": "^7.14.5",
     "@babel/types": "^7.12.1",
-    "@embroider/core": "0.42.3",
+    "@embroider/core": "0.43.0",
     "@embroider/test-support": "0.36.0",
     "@types/babel__core": "^7.1.14",
     "@types/babel__generator": "^7.6.2",
diff --git a/packages/router/package.json b/packages/router/package.json
index bbedc4071..f64fc621e 100644
--- a/packages/router/package.json
+++ b/packages/router/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/router",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "description": "Lazy loading router",
   "keywords": [
     "ember-addon"
@@ -28,16 +28,16 @@
     "test:classic": "cross-env CLASSIC=true ember test --test-port=0"
   },
   "dependencies": {
-    "@embroider/macros": "0.42.3",
+    "@embroider/macros": "0.43.0",
     "ember-cli-babel": "^7.23.0"
   },
   "devDependencies": {
     "@ember/optional-features": "^0.7.0",
     "@ember/string": "^1.0.0",
-    "@embroider/compat": "0.42.3",
-    "@embroider/core": "0.42.3",
+    "@embroider/compat": "0.43.0",
+    "@embroider/core": "0.43.0",
     "@embroider/test-support": "0.36.0",
-    "@embroider/webpack": "0.42.3",
+    "@embroider/webpack": "0.43.0",
     "@types/ember__routing": "^3.16.9",
     "babel-eslint": "^10.1.0",
     "broccoli-asset-rev": "^3.0.0",
@@ -66,7 +66,7 @@
     "qunit-dom": "^0.8.4"
   },
   "peerDependencies": {
-    "@embroider/core": "0.42.3",
+    "@embroider/core": "0.43.0",
     "@types/ember__routing": "*"
   },
   "peerDependenciesMeta": {
diff --git a/packages/shared-internals/package.json b/packages/shared-internals/package.json
index 17e85ec64..c6cc97a4c 100644
--- a/packages/shared-internals/package.json
+++ b/packages/shared-internals/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/shared-internals",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "Utilities shared among the other embroider packages",
   "repository": {
diff --git a/packages/test-setup/package.json b/packages/test-setup/package.json
index 23c90c30e..40e2e9d1b 100644
--- a/packages/test-setup/package.json
+++ b/packages/test-setup/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/test-setup",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "repository": {
     "type": "git",
     "url": "https://github.com/embroider-build/embroider.git",
@@ -16,7 +16,7 @@
     "resolve": "^1.20.0"
   },
   "devDependencies": {
-    "@embroider/compat": "0.42.3"
+    "@embroider/compat": "0.43.0"
   },
   "engines": {
     "node": "12.* || 14.* || >= 16"
diff --git a/packages/util/package.json b/packages/util/package.json
index 4dee0c3f4..57d2e1017 100644
--- a/packages/util/package.json
+++ b/packages/util/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/util",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "description": "Utilities for app and addon authors.",
   "keywords": [
     "ember-addon"
@@ -28,18 +28,18 @@
     "test:ember-compatibility": "ember try:each"
   },
   "dependencies": {
-    "@embroider/macros": "0.42.3",
+    "@embroider/macros": "0.43.0",
     "broccoli-funnel": "^3.0.5",
     "ember-cli-babel": "^7.23.1"
   },
   "devDependencies": {
     "@ember/optional-features": "^2.0.0",
     "@ember/test-helpers": "^2.2.0",
-    "@embroider/compat": "0.42.3",
-    "@embroider/core": "0.42.3",
-    "@embroider/test-setup": "0.42.3",
+    "@embroider/compat": "0.43.0",
+    "@embroider/core": "0.43.0",
+    "@embroider/test-setup": "0.43.0",
     "@embroider/test-support": "0.36.0",
-    "@embroider/webpack": "0.42.3",
+    "@embroider/webpack": "0.43.0",
     "@glimmer/component": "^1.0.3",
     "@glimmer/tracking": "^1.0.3",
     "@typescript-eslint/eslint-plugin": "^4.1.1",
diff --git a/packages/webpack/package.json b/packages/webpack/package.json
index 329aba910..51852634f 100644
--- a/packages/webpack/package.json
+++ b/packages/webpack/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@embroider/webpack",
-  "version": "0.42.3",
+  "version": "0.43.0",
   "private": false,
   "description": "Builds EmberJS apps with Webpack",
   "repository": {
@@ -23,9 +23,9 @@
     "@babel/core": "^7.14.5",
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.14.5",
     "@babel/plugin-proposal-optional-chaining": "^7.14.5",
-    "@embroider/babel-loader-8": "0.42.3",
-    "@embroider/hbs-loader": "0.42.3",
-    "@embroider/shared-internals": "0.42.3",
+    "@embroider/babel-loader-8": "0.43.0",
+    "@embroider/hbs-loader": "0.43.0",
+    "@embroider/shared-internals": "0.43.0",
     "@types/loader-utils": "^2.0.2",
     "@types/source-map": "^0.5.7",
     "@types/supports-color": "^8.1.0",
@@ -56,7 +56,7 @@
     "webpack": "^5.38.1"
   },
   "peerDependencies": {
-    "@embroider/core": "0.42.3",
+    "@embroider/core": "0.43.0",
     "webpack": "^5.0.0"
   },
   "engines": {
diff --git a/test-packages/macro-sample-addon/package.json b/test-packages/macro-sample-addon/package.json
index e3abecd32..6eea79e46 100644
--- a/test-packages/macro-sample-addon/package.json
+++ b/test-packages/macro-sample-addon/package.json
@@ -24,17 +24,17 @@
     "test:classic:": "cross-env CLASSIC=true ember test --test-port=0"
   },
   "dependencies": {
-    "@embroider/macros": "0.42.3",
+    "@embroider/macros": "0.43.0",
     "ember-cli-babel": "^7.20.5",
     "ember-cli-htmlbars": "^4.3.1"
   },
   "devDependencies": {
     "@ember/optional-features": "^0.7.0",
     "@ember/string": "^1.0.0",
-    "@embroider/compat": "0.42.3",
-    "@embroider/core": "0.42.3",
+    "@embroider/compat": "0.43.0",
+    "@embroider/core": "0.43.0",
     "@embroider/test-support": "0.36.0",
-    "@embroider/webpack": "0.42.3",
+    "@embroider/webpack": "0.43.0",
     "broccoli-asset-rev": "^3.0.0",
     "ember-cli-dependency-checker": "^3.1.0",
     "ember-cli": "~3.26.1",
diff --git a/tests/addon-template/package.json b/tests/addon-template/package.json
index 6b0b4d3d2..c20027d5e 100644
--- a/tests/addon-template/package.json
+++ b/tests/addon-template/package.json
@@ -32,7 +32,7 @@
   "devDependencies": {
     "@ember/optional-features": "^2.0.0",
     "@ember/test-helpers": "^2.2.5",
-    "@embroider/test-setup": "^0.42.3",
+    "@embroider/test-setup": "^0.43.0",
     "@glimmer/component": "^1.0.4",
     "@glimmer/tracking": "^1.0.4",
     "babel-eslint": "^10.1.0",
diff --git a/tests/app-template/package.json b/tests/app-template/package.json
index c8e365066..379569248 100644
--- a/tests/app-template/package.json
+++ b/tests/app-template/package.json
@@ -26,10 +26,10 @@
   "devDependencies": {
     "@ember/optional-features": "^2.0.0",
     "@ember/test-helpers": "^2.2.5",
-    "@embroider/compat": "0.42.3",
-    "@embroider/core": "0.42.3",
-    "@embroider/webpack": "0.42.3",
-    "@embroider/router": "0.42.3",
+    "@embroider/compat": "0.43.0",
+    "@embroider/core": "0.43.0",
+    "@embroider/webpack": "0.43.0",
+    "@embroider/router": "0.43.0",
     "@glimmer/component": "^1.0.4",
     "@glimmer/tracking": "^1.0.4",
     "babel-eslint": "^10.1.0",
diff --git a/tests/scenarios/package.json b/tests/scenarios/package.json
index 7c78df2d5..bd42a7ba1 100644
--- a/tests/scenarios/package.json
+++ b/tests/scenarios/package.json
@@ -18,7 +18,7 @@
   },
   "license": "MIT",
   "devDependencies": {
-    "@embroider/macros": "0.42.3",
+    "@embroider/macros": "0.43.0",
     "bootstrap": "^4.3.1",
     "broccoli-funnel": "^3.0.5",
     "broccoli-merge-trees": "^3.0.2",