diff --git a/src/commands/libcoreGetVersion.js b/src/commands/libcoreGetVersion.js
index 43a9924f..e8fbd065 100644
--- a/src/commands/libcoreGetVersion.js
+++ b/src/commands/libcoreGetVersion.js
@@ -11,7 +11,7 @@ type Result = { stringVersion: string, intVersion: number }
 
 const cmd: Command<Input, Result> = createCommand('libcoreGetVersion', () =>
   fromPromise(
-    withLibcore(ledgerCore => {
+    withLibcore(async ledgerCore => {
       const core = new ledgerCore.NJSLedgerCore()
       const stringVersion = core.getStringVersion()
       const intVersion = core.getIntVersion()
diff --git a/src/commands/libcoreSignAndBroadcast.js b/src/commands/libcoreSignAndBroadcast.js
index 8ae4d954..22324197 100644
--- a/src/commands/libcoreSignAndBroadcast.js
+++ b/src/commands/libcoreSignAndBroadcast.js
@@ -4,6 +4,7 @@ import type { AccountRaw, OperationRaw } from '@ledgerhq/live-common/lib/types'
 import Btc from '@ledgerhq/hw-app-btc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
 import { getCryptoCurrencyById } from '@ledgerhq/live-common/lib/helpers/currencies'
+import type Transport from '@ledgerhq/hw-transport'
 
 import withLibcore from 'helpers/withLibcore'
 import { createCommand, Command } from 'helpers/ipc'
@@ -42,7 +43,19 @@ const cmd: Command<Input, Result> = createCommand(
     ),
 )
 
-export async function doSignAndBroadcast({ account, transaction, deviceId, core, transport }) {
+export async function doSignAndBroadcast({
+  account,
+  transaction,
+  deviceId,
+  core,
+  transport,
+}: {
+  account: AccountRaw,
+  transaction: BitcoinLikeTransaction,
+  deviceId: string,
+  core: *,
+  transport: Transport<*>,
+}) {
   const hwApp = new Btc(transport)
 
   const WALLET_IDENTIFIER = await getWalletIdentifier({
diff --git a/src/helpers/accountId.js b/src/helpers/accountId.js
index b70b5cef..543a8223 100644
--- a/src/helpers/accountId.js
+++ b/src/helpers/accountId.js
@@ -1,16 +1,22 @@
 // @flow
 
+import invariant from 'invariant'
+
 type Params = {
   type: string,
+  version: string,
   xpub: string,
   walletName: string,
 }
 
-export function encode({ type, xpub, walletName }: Params) {
-  return `${type}:${xpub}:${walletName}`
+export function encode({ type, version, xpub, walletName }: Params) {
+  return `${type}:${version}:${xpub}:${walletName}`
 }
 
-export function decode(accountId: string) {
-  const [type, xpub, walletName] = accountId.split(':')
-  return { type, xpub, walletName }
+export function decode(accountId: string): Params {
+  invariant(typeof accountId === 'string', 'accountId is not a string')
+  const splitted = accountId.split(':')
+  invariant(splitted.length === 4, 'invalid size for accountId')
+  const [type, version, xpub, walletName] = splitted
+  return { type, version, xpub, walletName }
 }
diff --git a/src/helpers/libcore.js b/src/helpers/libcore.js
index 2a09a3a4..6fd035d1 100644
--- a/src/helpers/libcore.js
+++ b/src/helpers/libcore.js
@@ -10,7 +10,7 @@ import type { NJSAccount, NJSOperation } from '@ledgerhq/ledger-core/src/ledgerc
 import * as accountIdHelper from 'helpers/accountId'
 
 type Props = {
-  core: Object,
+  core: *,
   devicePath: string,
   currencyId: string,
   onAccountScanned: AccountRaw => void,
@@ -82,7 +82,7 @@ async function scanAccountsOnDeviceBySegwit({
   isSegwit,
   showNewAccount,
 }: {
-  core: Object,
+  core: *,
   hwApp: Object,
   currencyId: string,
   onAccountScanned: AccountRaw => void,
@@ -118,7 +118,7 @@ async function scanAccountsOnDeviceBySegwit({
 async function scanNextAccount(props: {
   // $FlowFixMe
   wallet: NJSWallet,
-  core: Object,
+  core: *,
   hwApp: Object,
   currencyId: string,
   accountsCount: number,
@@ -183,7 +183,7 @@ async function scanNextAccount(props: {
 }
 
 async function getOrCreateWallet(
-  core: Object,
+  core: *,
   WALLET_IDENTIFIER: string,
   currencyId: string,
   isSegwit: boolean,
@@ -220,7 +220,7 @@ async function buildAccountRaw({
   wallet: NJSWallet,
   currencyId: string,
   accountIndex: number,
-  core: Object,
+  core: *,
   // $FlowFixMe
   ops: NJSOperation[],
 }): Promise<AccountRaw> {
@@ -262,7 +262,12 @@ async function buildAccountRaw({
   }
 
   const rawAccount: AccountRaw = {
-    id: accountIdHelper.encode({ type: 'libcore', xpub, walletName: wallet.getName() }),
+    id: accountIdHelper.encode({
+      type: 'libcore',
+      version: '1',
+      xpub,
+      walletName: wallet.getName(),
+    }),
     xpub,
     path: walletPath,
     name,
@@ -288,7 +293,7 @@ function buildOperationRaw({
   op,
   xpub,
 }: {
-  core: Object,
+  core: *,
   op: NJSOperation,
   xpub: string,
 }): OperationRaw {
@@ -322,15 +327,15 @@ function buildOperationRaw({
 }
 
 export async function getNJSAccount({
-  account,
+  accountRaw,
   njsWalletPool,
 }: {
-  accountId: string,
-  njsWalletPool: any,
+  accountRaw: AccountRaw,
+  njsWalletPool: *,
 }) {
-  const decodedAccountId = accountIdHelper.decode(account.id)
+  const decodedAccountId = accountIdHelper.decode(accountRaw.id)
   const njsWallet = await njsWalletPool.getWallet(decodedAccountId.walletName)
-  const njsAccount = await njsWallet.getAccount(account.index)
+  const njsAccount = await njsWallet.getAccount(accountRaw.index)
   return njsAccount
 }
 
@@ -339,9 +344,9 @@ export async function syncAccount({
   core,
   njsWalletPool,
 }: {
-  core: Object,
+  core: *,
   rawAccount: AccountRaw,
-  njsWalletPool: Object,
+  njsWalletPool: *,
 }) {
   const decodedAccountId = accountIdHelper.decode(rawAccount.id)
   const njsWallet = await njsWalletPool.getWallet(decodedAccountId.walletName)