diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a8d88843a..1555848416 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## 1.21.0-beta.x
 
+- Add support for `CheckMortality` signed extension (old `CheckEra` is now an alias)
 - Fix subscriptions never unsubscribing after the id type swap in 1.18.1
 - Promise API will default to using `getStorage` on non-subscription calls, reducing RPC overhead
 - Optimize derive BN allocations, using in-place operators as applicable
diff --git a/packages/types/src/extrinsic/signedExtensions/emptyCheck.ts b/packages/types/src/extrinsic/signedExtensions/emptyCheck.ts
new file mode 100644
index 0000000000..5896ad6b5e
--- /dev/null
+++ b/packages/types/src/extrinsic/signedExtensions/emptyCheck.ts
@@ -0,0 +1,8 @@
+// Copyright 2017-2020 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+export default {
+  extra: {},
+  types: {}
+};
diff --git a/packages/types/src/extrinsic/signedExtensions/polkadot.ts b/packages/types/src/extrinsic/signedExtensions/polkadot.ts
index d077f008f7..cf1c3bedb8 100644
--- a/packages/types/src/extrinsic/signedExtensions/polkadot.ts
+++ b/packages/types/src/extrinsic/signedExtensions/polkadot.ts
@@ -4,29 +4,13 @@
 
 import { ExtDef } from './types';
 
+import EmptyCheck from './emptyCheck';
+
 export default {
-  LimitParathreadCommits: {
-    extra: {},
-    types: {}
-  },
-  OnlyStakingAndClaims: {
-    extra: {},
-    types: {}
-  },
-  PrevalidateAttests: {
-    extra: {},
-    types: {}
-  },
-  RestrictFunctionality: {
-    extra: {},
-    types: {}
-  },
-  TransactionCallFilter: {
-    extra: {},
-    types: {}
-  },
-  ValidateDoubleVoteReports: {
-    extra: {},
-    types: {}
-  }
+  LimitParathreadCommits: EmptyCheck,
+  OnlyStakingAndClaims: EmptyCheck,
+  PrevalidateAttests: EmptyCheck,
+  RestrictFunctionality: EmptyCheck,
+  TransactionCallFilter: EmptyCheck,
+  ValidateDoubleVoteReports: EmptyCheck
 } as ExtDef;
diff --git a/packages/types/src/extrinsic/signedExtensions/substrate.ts b/packages/types/src/extrinsic/signedExtensions/substrate.ts
index 7574c14b63..6fa9015d9c 100644
--- a/packages/types/src/extrinsic/signedExtensions/substrate.ts
+++ b/packages/types/src/extrinsic/signedExtensions/substrate.ts
@@ -4,6 +4,17 @@
 
 import { ExtDef } from './types';
 
+import EmptyCheck from './emptyCheck';
+
+const CheckMortality = {
+  extra: {
+    blockHash: 'Hash'
+  },
+  types: {
+    era: 'ExtrinsicEra'
+  }
+};
+
 export default {
   ChargeTransactionPayment: {
     extra: {},
@@ -11,24 +22,15 @@ export default {
       tip: 'Compact<Balance>'
     }
   },
-  CheckBlockGasLimit: {
-    extra: {},
-    types: {}
-  },
-  CheckEra: {
-    extra: {
-      blockHash: 'Hash'
-    },
-    types: {
-      era: 'ExtrinsicEra'
-    }
-  },
+  CheckBlockGasLimit: EmptyCheck,
+  CheckEra: CheckMortality,
   CheckGenesis: {
     extra: {
       genesisHash: 'Hash'
     },
     types: {}
   },
+  CheckMortality,
   CheckNonce: {
     extra: {},
     types: {
@@ -53,16 +55,7 @@ export default {
     },
     types: {}
   },
-  CheckWeight: {
-    extra: {},
-    types: {}
-  },
-  LockStakingStatus: {
-    extra: {},
-    types: {}
-  },
-  ValidateEquivocationReport: {
-    extra: {},
-    types: {}
-  }
+  CheckWeight: EmptyCheck,
+  LockStakingStatus: EmptyCheck,
+  ValidateEquivocationReport: EmptyCheck
 } as ExtDef;