diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0514bdc213..70dc23c627 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,23 @@
 # CHANGELOG
 
+## 4.2.1 Mar 22, 2021
+
+Upgrade priority: Low. Recommended when tracking the latest updates from Substrate.
+
+Contributed:
+
+- Fix contract even decoding on Substrate 3 (Thanks to https://github.com/vminkov)
+
+Changes:
+
+- Adjust `Extender{Header, SignedBlock}` types to ensure at-block `Header` types are used
+- Explicit definition for new Rococo triple refcount `AccountData` types
+- Convert metadata private class fields to ES-private
+- Adjust `SignedBlock` type for new `justifications` field
+- Optimize society derive for multi accounts
+- Bump metadata to latest substrate version
+
+
 ## 4.1.1 Mar 15, 2021
 
 Upgrade priority: Low. Recommended when tracking the latest updates from Substrate.
diff --git a/package.json b/package.json
index 76aa9d95e1..e0db5e2f1d 100644
--- a/package.json
+++ b/package.json
@@ -34,5 +34,5 @@
     "@types/jest": "^26.0.21",
     "copyfiles": "^2.4.1"
   },
-  "version": "4.1.2-8"
+  "version": "4.2.0"
 }
diff --git a/packages/api-contract/package.json b/packages/api-contract/package.json
index f929d9637b..d27a8bf6dc 100644
--- a/packages/api-contract/package.json
+++ b/packages/api-contract/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-contract",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Interfaces for interacting with contracts and contract ABIs",
   "main": "index.js",
@@ -17,8 +17,8 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-contract#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/api": "4.1.2-8",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/api": "4.2.0",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/x-rxjs": "^6.0.5",
     "bn.js": "^4.11.9"
diff --git a/packages/api-derive/package.json b/packages/api-derive/package.json
index 45369be235..82e6cd4216 100644
--- a/packages/api-derive/package.json
+++ b/packages/api-derive/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-derive",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Common functions used across Polkadot, derived from RPC calls and storage queries.",
   "main": "index.js",
@@ -17,9 +17,9 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-derive#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/api": "4.1.2-8",
-    "@polkadot/rpc-core": "4.1.2-8",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/api": "4.2.0",
+    "@polkadot/rpc-core": "4.2.0",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/util-crypto": "^6.0.5",
     "@polkadot/x-rxjs": "^6.0.5",
@@ -27,6 +27,6 @@
   },
   "devDependencies": {
     "@polkadot/keyring": "^6.0.5",
-    "@polkadot/rpc-provider": "4.1.2-8"
+    "@polkadot/rpc-provider": "4.2.0"
   }
 }
diff --git a/packages/api/package.json b/packages/api/package.json
index 9afad73b0d..0b734c04b7 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Promise and RxJS wrappers around the Polkadot JS RPC",
   "main": "index.js",
@@ -17,13 +17,13 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/api-derive": "4.1.2-8",
+    "@polkadot/api-derive": "4.2.0",
     "@polkadot/keyring": "^6.0.5",
-    "@polkadot/metadata": "4.1.2-8",
-    "@polkadot/rpc-core": "4.1.2-8",
-    "@polkadot/rpc-provider": "4.1.2-8",
-    "@polkadot/types": "4.1.2-8",
-    "@polkadot/types-known": "4.1.2-8",
+    "@polkadot/metadata": "4.2.0",
+    "@polkadot/rpc-core": "4.2.0",
+    "@polkadot/rpc-provider": "4.2.0",
+    "@polkadot/types": "4.2.0",
+    "@polkadot/types-known": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/util-crypto": "^6.0.5",
     "@polkadot/x-rxjs": "^6.0.5",
diff --git a/packages/metadata/package.json b/packages/metadata/package.json
index 1323f45da4..d104090df8 100644
--- a/packages/metadata/package.json
+++ b/packages/metadata/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/metadata",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Helpers to extract information from runtime metadata",
   "main": "index.js",
@@ -17,8 +17,8 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/type-metadata#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/types": "4.1.2-8",
-    "@polkadot/types-known": "4.1.2-8",
+    "@polkadot/types": "4.2.0",
+    "@polkadot/types-known": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/util-crypto": "^6.0.5",
     "bn.js": "^4.11.9"
diff --git a/packages/rpc-core/package.json b/packages/rpc-core/package.json
index 2e5b315d27..30d09f54f6 100644
--- a/packages/rpc-core/package.json
+++ b/packages/rpc-core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/rpc-core",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "A JavaScript wrapper for the Polkadot JsonRPC interface",
   "main": "index.js",
@@ -17,9 +17,9 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/rpc-core#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/metadata": "4.1.2-8",
-    "@polkadot/rpc-provider": "4.1.2-8",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/metadata": "4.2.0",
+    "@polkadot/rpc-provider": "4.2.0",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/x-rxjs": "^6.0.5"
   },
diff --git a/packages/rpc-provider/package.json b/packages/rpc-provider/package.json
index 13f3c0adc0..bef07d0daa 100644
--- a/packages/rpc-provider/package.json
+++ b/packages/rpc-provider/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/rpc-provider",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Transport providers for the API",
   "main": "index.js",
@@ -17,7 +17,7 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/rpc-provider#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/util-crypto": "^6.0.5",
     "@polkadot/x-fetch": "^6.0.5",
@@ -28,7 +28,7 @@
   },
   "devDependencies": {
     "@polkadot/keyring": "^6.0.5",
-    "@polkadot/metadata": "4.1.2-8",
+    "@polkadot/metadata": "4.2.0",
     "mock-socket": "^9.0.3",
     "nock": "^13.0.11"
   }
diff --git a/packages/typegen/package.json b/packages/typegen/package.json
index 7b87c46d8b..a998370986 100644
--- a/packages/typegen/package.json
+++ b/packages/typegen/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/typegen",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Type generation scripts",
   "main": "index.js",
@@ -26,10 +26,10 @@
     "@babel/core": "^7.13.10",
     "@babel/register": "^7.13.8",
     "@babel/runtime": "^7.13.10",
-    "@polkadot/api": "4.1.2-8",
-    "@polkadot/metadata": "4.1.2-8",
-    "@polkadot/rpc-provider": "4.1.2-8",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/api": "4.2.0",
+    "@polkadot/metadata": "4.2.0",
+    "@polkadot/rpc-provider": "4.2.0",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "handlebars": "^4.7.7",
     "websocket": "^1.0.33",
diff --git a/packages/types-known/package.json b/packages/types-known/package.json
index 8c77f40b4c..9aa8053bf1 100644
--- a/packages/types-known/package.json
+++ b/packages/types-known/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/types-known",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "A JavaScript wrapper for the Polkadot JsonRPC interface",
   "main": "index.js",
@@ -18,7 +18,7 @@
   "dependencies": {
     "@babel/runtime": "^7.13.10",
     "@polkadot/networks": "^6.0.5",
-    "@polkadot/types": "4.1.2-8",
+    "@polkadot/types": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "bn.js": "^4.11.9"
   },
diff --git a/packages/types/package.json b/packages/types/package.json
index 3a2f1ad03f..2d4fd0fe5c 100644
--- a/packages/types/package.json
+++ b/packages/types/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/types",
-  "version": "4.1.2-8",
+  "version": "4.2.0",
   "type": "module",
   "description": "Implementation of the Parity codec",
   "main": "index.js",
@@ -17,7 +17,7 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/types#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@polkadot/metadata": "4.1.2-8",
+    "@polkadot/metadata": "4.2.0",
     "@polkadot/util": "^6.0.5",
     "@polkadot/util-crypto": "^6.0.5",
     "@polkadot/x-rxjs": "^6.0.5",
diff --git a/yarn.lock b/yarn.lock
index 2f1858dc06..421b7b00d8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1778,24 +1778,24 @@ __metadata:
   resolution: "@polkadot/api-contract@workspace:packages/api-contract"
   dependencies:
     "@babel/runtime": ^7.13.10
-    "@polkadot/api": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/api": 4.2.0
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/x-rxjs": ^6.0.5
     bn.js: ^4.11.9
   languageName: unknown
   linkType: soft
 
-"@polkadot/api-derive@4.1.2-8, @polkadot/api-derive@workspace:packages/api-derive":
+"@polkadot/api-derive@4.2.0, @polkadot/api-derive@workspace:packages/api-derive":
   version: 0.0.0-use.local
   resolution: "@polkadot/api-derive@workspace:packages/api-derive"
   dependencies:
     "@babel/runtime": ^7.13.10
-    "@polkadot/api": 4.1.2-8
+    "@polkadot/api": 4.2.0
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/rpc-core": 4.1.2-8
-    "@polkadot/rpc-provider": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/rpc-core": 4.2.0
+    "@polkadot/rpc-provider": 4.2.0
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/util-crypto": ^6.0.5
     "@polkadot/x-rxjs": ^6.0.5
@@ -1803,18 +1803,18 @@ __metadata:
   languageName: unknown
   linkType: soft
 
-"@polkadot/api@4.1.2-8, @polkadot/api@workspace:packages/api":
+"@polkadot/api@4.2.0, @polkadot/api@workspace:packages/api":
   version: 0.0.0-use.local
   resolution: "@polkadot/api@workspace:packages/api"
   dependencies:
     "@babel/runtime": ^7.13.10
-    "@polkadot/api-derive": 4.1.2-8
+    "@polkadot/api-derive": 4.2.0
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/metadata": 4.1.2-8
-    "@polkadot/rpc-core": 4.1.2-8
-    "@polkadot/rpc-provider": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
-    "@polkadot/types-known": 4.1.2-8
+    "@polkadot/metadata": 4.2.0
+    "@polkadot/rpc-core": 4.2.0
+    "@polkadot/rpc-provider": 4.2.0
+    "@polkadot/types": 4.2.0
+    "@polkadot/types-known": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/util-crypto": ^6.0.5
     "@polkadot/x-rxjs": ^6.0.5
@@ -1923,14 +1923,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@polkadot/metadata@4.1.2-8, @polkadot/metadata@workspace:packages/metadata":
+"@polkadot/metadata@4.2.0, @polkadot/metadata@workspace:packages/metadata":
   version: 0.0.0-use.local
   resolution: "@polkadot/metadata@workspace:packages/metadata"
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/types": 4.1.2-8
-    "@polkadot/types-known": 4.1.2-8
+    "@polkadot/types": 4.2.0
+    "@polkadot/types-known": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/util-crypto": ^6.0.5
     bn.js: ^4.11.9
@@ -1946,28 +1946,28 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@polkadot/rpc-core@4.1.2-8, @polkadot/rpc-core@workspace:packages/rpc-core":
+"@polkadot/rpc-core@4.2.0, @polkadot/rpc-core@workspace:packages/rpc-core":
   version: 0.0.0-use.local
   resolution: "@polkadot/rpc-core@workspace:packages/rpc-core"
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/metadata": 4.1.2-8
-    "@polkadot/rpc-provider": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/metadata": 4.2.0
+    "@polkadot/rpc-provider": 4.2.0
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/x-rxjs": ^6.0.5
   languageName: unknown
   linkType: soft
 
-"@polkadot/rpc-provider@4.1.2-8, @polkadot/rpc-provider@workspace:packages/rpc-provider":
+"@polkadot/rpc-provider@4.2.0, @polkadot/rpc-provider@workspace:packages/rpc-provider":
   version: 0.0.0-use.local
   resolution: "@polkadot/rpc-provider@workspace:packages/rpc-provider"
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/metadata": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/metadata": 4.2.0
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/util-crypto": ^6.0.5
     "@polkadot/x-fetch": ^6.0.5
@@ -1996,10 +1996,10 @@ __metadata:
     "@babel/core": ^7.13.10
     "@babel/register": ^7.13.8
     "@babel/runtime": ^7.13.10
-    "@polkadot/api": 4.1.2-8
-    "@polkadot/metadata": 4.1.2-8
-    "@polkadot/rpc-provider": 4.1.2-8
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/api": 4.2.0
+    "@polkadot/metadata": 4.2.0
+    "@polkadot/rpc-provider": 4.2.0
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@types/websocket": ^1.0.2
     "@types/yargs": ^16.0.0
@@ -2015,26 +2015,26 @@ __metadata:
   languageName: unknown
   linkType: soft
 
-"@polkadot/types-known@4.1.2-8, @polkadot/types-known@workspace:packages/types-known":
+"@polkadot/types-known@4.2.0, @polkadot/types-known@workspace:packages/types-known":
   version: 0.0.0-use.local
   resolution: "@polkadot/types-known@workspace:packages/types-known"
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/networks": ^6.0.5
-    "@polkadot/types": 4.1.2-8
+    "@polkadot/types": 4.2.0
     "@polkadot/util": ^6.0.5
     "@types/bn.js": ^4.11.6
     bn.js: ^4.11.9
   languageName: unknown
   linkType: soft
 
-"@polkadot/types@4.1.2-8, @polkadot/types@workspace:packages/types":
+"@polkadot/types@4.2.0, @polkadot/types@workspace:packages/types":
   version: 0.0.0-use.local
   resolution: "@polkadot/types@workspace:packages/types"
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/keyring": ^6.0.5
-    "@polkadot/metadata": 4.1.2-8
+    "@polkadot/metadata": 4.2.0
     "@polkadot/util": ^6.0.5
     "@polkadot/util-crypto": ^6.0.5
     "@polkadot/x-rxjs": ^6.0.5