diff --git a/docs/METHODS_CONSTANTS.md b/docs/METHODS_CONSTANTS.md
index e35835df3d..5fc0d37fb5 100644
--- a/docs/METHODS_CONSTANTS.md
+++ b/docs/METHODS_CONSTANTS.md
@@ -1,6 +1,8 @@
 ## Constants
 
 _The following sections contain the module constants, also known as parameter types.
+- **[babe](#babe)**
+
 - **[balances](#balances)**
 
 - **[contracts](#contracts)**
@@ -25,6 +27,17 @@ _The following sections contain the module constants, also known as parameter ty
 ___
 
 
+### babe
+
+▸ **epochDuration**: `u64`
+- **summary**:   The number of **slots** that an epoch takes. We couple sessions to  epochs, i.e. we start a new session once the new epoch begins.
+
+▸ **expectedBlockTime**: `Moment`
+- **summary**:   The expected average block time at which BABE should be creating  blocks. Since BABE is probabilistic it is not trivial to figure out  what the expected average block time should be based on the slot  duration and the security parameter `c` (where `1 - c` represents  the probability of a slot being empty).
+
+___
+
+
 ### balances
 
 ▸ **creationFee**: `Balance`
diff --git a/lerna.json b/lerna.json
index 0140d33ba7..8fccad5d7c 100644
--- a/lerna.json
+++ b/lerna.json
@@ -9,5 +9,5 @@
   "packages": [
     "packages/*"
   ],
-  "version": "0.90.0-beta.5"
+  "version": "0.90.0-beta.6"
 }
diff --git a/package.json b/package.json
index bdd6fba2e0..f395180e7c 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "private": true,
   "engines": {
     "yarn": "^1.10.1"
diff --git a/packages/api-contract/package.json b/packages/api-contract/package.json
index be01063fc3..8db74e44eb 100644
--- a/packages/api-contract/package.json
+++ b/packages/api-contract/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-contract",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Interfaces for interacting with contracts and contract ABIs",
   "main": "index.js",
   "keywords": [
@@ -27,6 +27,6 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-contract#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/types": "^0.90.0-beta.5"
+    "@polkadot/types": "^0.90.0-beta.6"
   }
 }
diff --git a/packages/api-derive/package.json b/packages/api-derive/package.json
index 6a54394607..d6138ae329 100644
--- a/packages/api-derive/package.json
+++ b/packages/api-derive/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-derive",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Common functions used across Polkadot, derived from RPC calls and storage queries.",
   "main": "index.js",
   "keywords": [
@@ -28,8 +28,8 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api-derive#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/api": "^0.90.0-beta.5",
-    "@polkadot/types": "^0.90.0-beta.5"
+    "@polkadot/api": "^0.90.0-beta.6",
+    "@polkadot/types": "^0.90.0-beta.6"
   },
   "devDependencies": {
     "@polkadot/keyring": "^0.95.0-beta.3"
diff --git a/packages/api-metadata/package.json b/packages/api-metadata/package.json
index eeccdf4a16..f4879ac742 100644
--- a/packages/api-metadata/package.json
+++ b/packages/api-metadata/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api-metadata",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Helpers to extract information from runtime metadata",
   "main": "index.js",
   "publishConfig": {
@@ -27,7 +27,7 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/type-metadata#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/types": "^0.90.0-beta.5",
+    "@polkadot/types": "^0.90.0-beta.6",
     "@polkadot/util": "^0.95.0-beta.3",
     "@polkadot/util-crypto": "^0.95.0-beta.3"
   },
diff --git a/packages/api/package.json b/packages/api/package.json
index 0f17c1f32c..dabd415da5 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/api",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Promise and RxJS wrappers around the Polkadot JS RPC",
   "main": "index.js",
   "keywords": [
@@ -27,11 +27,11 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/api#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/api-derive": "^0.90.0-beta.5",
-    "@polkadot/api-metadata": "^0.90.0-beta.5",
-    "@polkadot/rpc-core": "^0.90.0-beta.5",
-    "@polkadot/rpc-provider": "^0.90.0-beta.5",
-    "@polkadot/types": "^0.90.0-beta.5",
+    "@polkadot/api-derive": "^0.90.0-beta.6",
+    "@polkadot/api-metadata": "^0.90.0-beta.6",
+    "@polkadot/rpc-core": "^0.90.0-beta.6",
+    "@polkadot/rpc-provider": "^0.90.0-beta.6",
+    "@polkadot/types": "^0.90.0-beta.6",
     "@polkadot/util-crypto": "^0.95.0-beta.3"
   },
   "devDependencies": {
diff --git a/packages/rpc-core/package.json b/packages/rpc-core/package.json
index dd5fd6a985..92e6cda63d 100644
--- a/packages/rpc-core/package.json
+++ b/packages/rpc-core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/rpc-core",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "A JavaScript wrapper for the Polkadot JsonRPC interface",
   "main": "index.js",
   "keywords": [
@@ -27,9 +27,9 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/rpc-core#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/jsonrpc": "^0.90.0-beta.5",
-    "@polkadot/rpc-provider": "^0.90.0-beta.5",
-    "@polkadot/types": "^0.90.0-beta.5",
+    "@polkadot/jsonrpc": "^0.90.0-beta.6",
+    "@polkadot/rpc-provider": "^0.90.0-beta.6",
+    "@polkadot/types": "^0.90.0-beta.6",
     "@polkadot/util": "^0.95.0-beta.3",
     "rxjs": "^6.5.2"
   }
diff --git a/packages/rpc-provider/package.json b/packages/rpc-provider/package.json
index ba08e97aec..ee8ed59122 100644
--- a/packages/rpc-provider/package.json
+++ b/packages/rpc-provider/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/rpc-provider",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Transport providers for the API",
   "main": "index.js",
   "keywords": [
@@ -27,7 +27,7 @@
   "homepage": "https://github.com/polkadot-js/api/tree/master/packages/rpc-provider#readme",
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@polkadot/api-metadata": "^0.90.0-beta.5",
+    "@polkadot/api-metadata": "^0.90.0-beta.6",
     "@polkadot/util": "^0.95.0-beta.3",
     "@polkadot/util-crypto": "^0.95.0-beta.3",
     "@types/nock": "^10.0.3",
diff --git a/packages/type-jsonrpc/package.json b/packages/type-jsonrpc/package.json
index 9b34b9c0c4..dbc9582ab1 100644
--- a/packages/type-jsonrpc/package.json
+++ b/packages/type-jsonrpc/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/jsonrpc",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Method definitions for the Polkadot RPC layer",
   "main": "index.js",
   "publishConfig": {
diff --git a/packages/types/package.json b/packages/types/package.json
index 1a1badf4db..be9a89dd2c 100644
--- a/packages/types/package.json
+++ b/packages/types/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/types",
-  "version": "0.90.0-beta.5",
+  "version": "0.90.0-beta.6",
   "description": "Implementation of the Parity codec",
   "main": "index.js",
   "keywords": [