diff --git a/src/components/AppLayout/InvalidMasterCopyError/InvalidMasterCopyError.test.tsx b/src/components/AppLayout/InvalidMasterCopyError/InvalidMasterCopyError.test.tsx
new file mode 100644
index 0000000000..0d92fc05a2
--- /dev/null
+++ b/src/components/AppLayout/InvalidMasterCopyError/InvalidMasterCopyError.test.tsx
@@ -0,0 +1,56 @@
+import { InvalidMasterCopyError } from './'
+import { render, waitFor, fireEvent } from 'src/utils/test-utils'
+import * as safeVersion from 'src/logic/safe/utils/safeVersion'
+import * as useAsync from 'src/logic/hooks/useAsync'
+
+describe('InvalidMasterCopyError', () => {
+  it('returns null if valid master copy', async () => {
+    jest.spyOn(safeVersion, 'isValidMasterCopy')
+    jest.spyOn(useAsync, 'default').mockImplementationOnce(() => [true, undefined, false])
+
+    const { container } = render(<InvalidMasterCopyError />)
+
+    await waitFor(() => {
+      expect(container.firstChild).toBeNull()
+    })
+  })
+
+  it('returns null if error', async () => {
+    jest.spyOn(safeVersion, 'isValidMasterCopy')
+    jest.spyOn(useAsync, 'default').mockImplementationOnce(() => [undefined, new Error(), false])
+
+    const { container } = render(<InvalidMasterCopyError />)
+
+    await waitFor(() => {
+      expect(container.firstChild).toBeNull()
+    })
+  })
+
+  it('displays an error message if not a valid master copy', async () => {
+    jest.spyOn(safeVersion, 'isValidMasterCopy')
+    jest.spyOn(useAsync, 'default').mockImplementationOnce(() => [false, undefined, false])
+
+    const { getByText } = render(<InvalidMasterCopyError />)
+
+    await waitFor(() => {
+      expect(getByText(/This Safe was created with an unsupported base contract/)).toBeInTheDocument()
+    })
+  })
+
+  it('hides the error message on close', async () => {
+    jest.spyOn(safeVersion, 'isValidMasterCopy')
+    jest.spyOn(useAsync, 'default').mockImplementation(() => [false, undefined, false])
+
+    const { getByText, queryByText, getByRole } = render(<InvalidMasterCopyError />)
+
+    await waitFor(() => {
+      expect(getByText(/This Safe was created with an unsupported base contract/)).toBeInTheDocument()
+    })
+
+    fireEvent.click(getByRole('button'))
+
+    await waitFor(() => {
+      expect(queryByText(/This Safe was created with an unsupported base contract/)).not.toBeInTheDocument()
+    })
+  })
+})
diff --git a/src/components/AppLayout/InvalidMasterCopyError/index.tsx b/src/components/AppLayout/InvalidMasterCopyError/index.tsx
new file mode 100644
index 0000000000..92d1423225
--- /dev/null
+++ b/src/components/AppLayout/InvalidMasterCopyError/index.tsx
@@ -0,0 +1,47 @@
+import { Link } from '@gnosis.pm/safe-react-components'
+import { useSelector } from 'react-redux'
+import { getChainInfo } from 'src/config'
+import { Errors, logError } from 'src/logic/exceptions/CodedException'
+import useAsync from 'src/logic/hooks/useAsync'
+import { currentSafe } from 'src/logic/safe/store/selectors'
+import { isValidMasterCopy } from 'src/logic/safe/utils/safeVersion'
+import MuiAlert from '@material-ui/lab/Alert'
+import { useState } from 'react'
+
+const CLI_LINK = 'https://github.com/5afe/safe-cli'
+
+export const InvalidMasterCopyError = (): React.ReactElement | null => {
+  const chainInfo = getChainInfo()
+  const { implementation } = useSelector(currentSafe)
+  const [showMasterCopyError, setShowMasterCopyError] = useState(true)
+
+  const [validMasterCopy, error] = useAsync(async () => {
+    if (implementation.value) {
+      return await isValidMasterCopy(chainInfo.chainId, implementation.value)
+    }
+  }, [chainInfo.chainId, implementation.value])
+
+  if (!showMasterCopyError) {
+    return null
+  }
+
+  if (error) {
+    logError(Errors._620, error.message)
+    return null
+  }
+
+  if (typeof validMasterCopy === 'undefined' || validMasterCopy) {
+    return null
+  }
+
+  return (
+    <MuiAlert severity="error" onClose={() => setShowMasterCopyError(false)}>
+      This Safe was created with an unsupported base contract. The web interface might not work correctly. We recommend
+      using the{' '}
+      <Link href={CLI_LINK} size="xl" target="_blank" rel="noopener noreferrer">
+        command line interface
+      </Link>{' '}
+      instead.
+    </MuiAlert>
+  )
+}
diff --git a/src/components/AppLayout/Sidebar/SafeHeader/index.tsx b/src/components/AppLayout/Sidebar/SafeHeader/index.tsx
index f943596be2..ff231714f3 100644
--- a/src/components/AppLayout/Sidebar/SafeHeader/index.tsx
+++ b/src/components/AppLayout/Sidebar/SafeHeader/index.tsx
@@ -76,6 +76,7 @@ const IconContainer = styled.div`
   display: flex;
   gap: 8px;
   justify-content: space-evenly;
+  align-items: center;
   margin: 14px 0;
 `
 const StyledButton = styled(Button)`
diff --git a/src/components/AppLayout/index.tsx b/src/components/AppLayout/index.tsx
index 2657dca456..625d8a090f 100644
--- a/src/components/AppLayout/index.tsx
+++ b/src/components/AppLayout/index.tsx
@@ -11,6 +11,7 @@ import { MobileNotSupported } from './MobileNotSupported'
 import { SAFE_APP_LANDING_PAGE_ROUTE, SAFE_ROUTES, WELCOME_ROUTE } from 'src/routes/routes'
 import useDarkMode from 'src/logic/hooks/useDarkMode'
 import { screenSm } from 'src/theme/variables'
+import { InvalidMasterCopyError } from 'src/components/AppLayout/InvalidMasterCopyError'
 
 const Container = styled.div`
   height: 100vh;
@@ -23,6 +24,7 @@ const Container = styled.div`
 
 const HeaderWrapper = styled.nav`
   height: 52px;
+  min-height: 52px;
   width: 100%;
   z-index: 1299;
 
@@ -157,6 +159,8 @@ const Layout: React.FC<Props> = ({
       <HeaderWrapper>
         <Header />
       </HeaderWrapper>
+      <InvalidMasterCopyError />
+
       <BodyWrapper>
         {showSideBar && (
           <SidebarWrapper data-testid="sidebar" $expanded={expanded} onClick={onSidebarClick}>
diff --git a/src/logic/contracts/safeContracts.ts b/src/logic/contracts/safeContracts.ts
index df6f6486e1..0dbe5db08b 100644
--- a/src/logic/contracts/safeContracts.ts
+++ b/src/logic/contracts/safeContracts.ts
@@ -6,6 +6,7 @@ import {
   getFallbackHandlerDeployment,
   getMultiSendCallOnlyDeployment,
   getSignMessageLibDeployment,
+  SingletonDeployment,
 } from '@gnosis.pm/safe-deployments'
 import Web3 from 'web3'
 import { AbiItem } from 'web3-utils'
@@ -22,6 +23,7 @@ import { CompatibilityFallbackHandler } from 'src/types/contracts/compatibility_
 import { SignMessageLib } from 'src/types/contracts/sign_message_lib.d'
 import { MultiSend } from 'src/types/contracts/multi_send.d'
 import { getSafeInfo } from 'src/logic/safe/utils/safeInformation'
+import { NonPayableTransactionObject } from 'src/types/contracts/types'
 
 export const SENTINEL_ADDRESS = '0x0000000000000000000000000000000000000001'
 
@@ -30,12 +32,13 @@ let safeMaster: GnosisSafe
 let fallbackHandler: CompatibilityFallbackHandler
 let multiSend: MultiSend
 
-const getSafeContractDeployment = ({ safeVersion }: { safeVersion: string }) => {
+const getSafeContractDeployment = ({ safeVersion }: { safeVersion: string }): SingletonDeployment | undefined => {
   // We check if version is prior to v1.0.0 as they are not supported but still we want to keep a minimum compatibility
   const useOldestContractVersion = semverSatisfies(safeVersion, '<1.0.0')
   // We have to check if network is L2
   const networkId = _getChainId()
   const chainConfig = getChainById(networkId)
+
   // We had L1 contracts in three L2 networks, xDai, EWC and Volta so even if network is L2 we have to check that safe version is after v1.3.0
   const useL2ContractVersion = chainConfig.l2 && semverSatisfies(safeVersion, '>=1.3.0')
   const getDeployment = useL2ContractVersion ? getSafeL2SingletonDeployment : getSafeSingletonDeployment
@@ -194,7 +197,7 @@ export const getMasterCopyAddressFromProxyAddress = async (proxyAddress: string)
   return masterCopyAddress
 }
 
-export const instantiateSafeContracts = () => {
+export const instantiateSafeContracts = (): void => {
   const web3 = getWeb3()
   const chainId = _getChainId()
 
@@ -211,24 +214,24 @@ export const instantiateSafeContracts = () => {
   multiSend = getMultiSendContractInstance(web3, chainId)
 }
 
-export const getSafeMasterContract = () => {
+export const getSafeMasterContract = (): GnosisSafe => {
   instantiateSafeContracts()
   return safeMaster
 }
 
-export const getSafeMasterContractAddress = () => {
+export const getSafeMasterContractAddress = (): string => {
   return safeMaster.options.address
 }
 
-export const getFallbackHandlerContractAddress = () => {
+export const getFallbackHandlerContractAddress = (): string => {
   return fallbackHandler.options.address
 }
 
-export const getMultisendContract = () => {
+export const getMultisendContract = (): MultiSend => {
   return multiSend
 }
 
-export const getMultisendContractAddress = () => {
+export const getMultisendContractAddress = (): string => {
   return multiSend.options.address
 }
 
@@ -236,7 +239,7 @@ export const getSafeDeploymentTransaction = (
   safeAccounts: string[],
   numConfirmations: number,
   safeCreationSalt: number,
-) => {
+): NonPayableTransactionObject<string> => {
   const gnosisSafeData = safeMaster.methods
     .setup(
       safeAccounts,
@@ -257,7 +260,7 @@ export const estimateGasForDeployingSafe = async (
   numConfirmations: number,
   userAccount: string,
   safeCreationSalt: number,
-) => {
+): Promise<number> => {
   const proxyFactoryData = getSafeDeploymentTransaction(safeAccounts, numConfirmations, safeCreationSalt).encodeABI()
 
   return calculateGasOf({
diff --git a/src/logic/exceptions/registry.ts b/src/logic/exceptions/registry.ts
index b516287475..b55bbdb84a 100644
--- a/src/logic/exceptions/registry.ts
+++ b/src/logic/exceptions/registry.ts
@@ -31,6 +31,7 @@ enum ErrorCodes {
   _617 = '617: Error fetching safeTxGas',
   _618 = '618: Error fetching fee history',
   _619 = '619: Failed to prepare a multisend tx',
+  _620 = '620: Failed to load master copy information',
   _700 = '700: Failed to read from local/session storage',
   _701 = '701: Failed to write to local/session storage',
   _702 = '702: Failed to remove from local/session storage',
diff --git a/src/logic/safe/store/actions/__tests__/utils.test.ts b/src/logic/safe/store/actions/__tests__/utils.test.ts
index 8666f2c0c7..a506d77f01 100644
--- a/src/logic/safe/store/actions/__tests__/utils.test.ts
+++ b/src/logic/safe/store/actions/__tests__/utils.test.ts
@@ -99,6 +99,12 @@ describe('extractRemoteSafeInfo', () => {
         'SAFE_TX_GAS_OPTIONAL',
         'SPENDING_LIMIT',
       ] as FEATURES[],
+      implementation: {
+        value: '0x3E5c63644E683549055b9Be8653de26E0B4CD36E',
+        name: 'Gnosis Safe: Mastercopy 1.3.0',
+        logoUri:
+          'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0x3E5c63644E683549055b9Be8653de26E0B4CD36E.png',
+      },
     }
 
     const remoteSafeInfo = await extractRemoteSafeInfo(remoteSafeInfoWithoutModules as any)
@@ -131,6 +137,12 @@ describe('extractRemoteSafeInfo', () => {
         'SAFE_TX_GAS_OPTIONAL',
         'SPENDING_LIMIT',
       ] as FEATURES[],
+      implementation: {
+        value: '0x3E5c63644E683549055b9Be8653de26E0B4CD36E',
+        name: 'Gnosis Safe: Mastercopy 1.3.0',
+        logoUri:
+          'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0x3E5c63644E683549055b9Be8653de26E0B4CD36E.png',
+      },
     }
 
     const remoteSafeInfo = await extractRemoteSafeInfo(remoteSafeInfoWithModules as any)
diff --git a/src/logic/safe/store/actions/mocks/safeInformation.ts b/src/logic/safe/store/actions/mocks/safeInformation.ts
index f219869b19..0e900632c0 100644
--- a/src/logic/safe/store/actions/mocks/safeInformation.ts
+++ b/src/logic/safe/store/actions/mocks/safeInformation.ts
@@ -29,7 +29,7 @@ export const remoteSafeInfoWithModules = {
   implementation: {
     value: '0x3E5c63644E683549055b9Be8653de26E0B4CD36E',
     name: 'Gnosis Safe: Mastercopy 1.3.0',
-    logoUrl:
+    logoUri:
       'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0x3E5c63644E683549055b9Be8653de26E0B4CD36E.png',
   },
   guard: {
@@ -43,7 +43,7 @@ export const remoteSafeInfoWithModules = {
   fallbackHandler: {
     value: '0xf48f2B2d2a534e402487b3ee7C18c33Aec0Fe5e4',
     name: 'Gnosis Safe: Default Callback Handler 1.3.0',
-    logoUrl:
+    logoUri:
       'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0xf48f2B2d2a534e402487b3ee7C18c33Aec0Fe5e4.png',
   },
   version: '1.3.0',
@@ -79,14 +79,14 @@ export const remoteSafeInfoWithoutModules = {
   implementation: {
     value: '0x3E5c63644E683549055b9Be8653de26E0B4CD36E',
     name: 'Gnosis Safe: Mastercopy 1.3.0',
-    logoUrl:
+    logoUri:
       'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0x3E5c63644E683549055b9Be8653de26E0B4CD36E.png',
   },
   modules: [],
   fallbackHandler: {
     value: '0xf48f2B2d2a534e402487b3ee7C18c33Aec0Fe5e4',
     name: 'Gnosis Safe: Default Callback Handler 1.3.0',
-    logoUrl:
+    logoUri:
       'https://safe-transaction-assets.staging.gnosisdev.com/contracts/logos/0xf48f2B2d2a534e402487b3ee7C18c33Aec0Fe5e4.png',
   },
   version: '1.3.0',
diff --git a/src/logic/safe/store/actions/utils.ts b/src/logic/safe/store/actions/utils.ts
index 559a5e3376..c4afc92a55 100644
--- a/src/logic/safe/store/actions/utils.ts
+++ b/src/logic/safe/store/actions/utils.ts
@@ -99,6 +99,7 @@ export const extractRemoteSafeInfo = async (remoteSafeInfo: SafeInfo): Promise<P
   safeInfo.txQueuedTag = remoteSafeInfo.txQueuedTag
   safeInfo.txHistoryTag = remoteSafeInfo.txHistoryTag
   safeInfo.chainId = remoteSafeInfo.chainId as ChainId
+  safeInfo.implementation = remoteSafeInfo.implementation
 
   return safeInfo
 }
diff --git a/src/logic/safe/store/models/safe.ts b/src/logic/safe/store/models/safe.ts
index 4004a06233..5f20e0ae9d 100644
--- a/src/logic/safe/store/models/safe.ts
+++ b/src/logic/safe/store/models/safe.ts
@@ -3,6 +3,7 @@ import { Record, RecordOf } from 'immutable'
 import { ChainId } from 'src/config/chain.d'
 
 import { BalanceRecord } from 'src/logic/tokens/store/actions/fetchSafeTokens'
+import { AddressEx } from '@gnosis.pm/safe-react-gateway-sdk/dist/types/common'
 
 export type SafeOwner = string
 
@@ -33,6 +34,7 @@ export type SafeRecordProps = {
   modules?: ModulePair[] | null
   spendingLimits?: SpendingLimit[] | null
   balances: BalanceRecord[]
+  implementation: AddressEx
   loaded: boolean
   nonce: number
   recurringUser?: boolean
@@ -59,6 +61,11 @@ const makeSafe = Record<SafeRecordProps>({
   modules: [],
   spendingLimits: [],
   balances: [],
+  implementation: {
+    value: '',
+    name: null,
+    logoUri: null,
+  },
   loaded: false,
   nonce: 0,
   recurringUser: undefined,
diff --git a/src/logic/safe/store/reducer/safe.ts b/src/logic/safe/store/reducer/safe.ts
index 7e5b621349..fd60e4eca2 100644
--- a/src/logic/safe/store/reducer/safe.ts
+++ b/src/logic/safe/store/reducer/safe.ts
@@ -51,6 +51,9 @@ const updateSafeProps = (prevSafe, safe) => {
           List.isList(safe[key])
             ? record.set(key, safe[key])
             : record.update(key, (current) => current.merge(safe[key]))
+        } else {
+          // TODO: temporary fix if type is AddressEx because it's neither a Map, nor has a size property
+          record.set(key, safe[key])
         }
       } else {
         // By default we overwrite the value. This is for strings, numbers and unset values
diff --git a/src/logic/safe/utils/__tests__/safeVersion.test.ts b/src/logic/safe/utils/__tests__/safeVersion.test.ts
index 10cfad951c..44ce634b55 100644
--- a/src/logic/safe/utils/__tests__/safeVersion.test.ts
+++ b/src/logic/safe/utils/__tests__/safeVersion.test.ts
@@ -1,5 +1,6 @@
 import { FEATURES } from '@gnosis.pm/safe-react-gateway-sdk'
-import { checkIfSafeNeedsUpdate, hasFeature } from 'src/logic/safe/utils/safeVersion'
+import * as GatewaySDK from '@gnosis.pm/safe-react-gateway-sdk'
+import { checkIfSafeNeedsUpdate, hasFeature, isValidMasterCopy } from 'src/logic/safe/utils/safeVersion'
 
 describe('Check safe version', () => {
   it('Calls checkIfSafeNeedUpdate, should return true if the safe version is bellow the target one', async () => {
@@ -36,4 +37,50 @@ describe('Check safe version', () => {
       expect(hasFeature(FEATURES.SAFE_APPS, '1.1.1')).toBe(true)
     })
   })
+
+  describe('isValidMasterCopy', () => {
+    it('returns false if address is not contained in result', async () => {
+      jest.spyOn(GatewaySDK, 'getMasterCopies').mockImplementation(() =>
+        Promise.resolve([
+          {
+            address: '0xd9Db270c1B5E3Bd161E8c8503c55cEABeE709552',
+            version: '1.3.0',
+            deployer: 'Gnosis',
+            deployedBlockNumber: 12504268,
+            lastIndexedBlockNumber: 14927028,
+            l2: false,
+          },
+        ]),
+      )
+
+      const isValid = await isValidMasterCopy('1', '0x0000000000000000000000000000000000000005')
+      expect(isValid).toBe(false)
+    })
+
+    it('returns true if address is contained in list', async () => {
+      jest.spyOn(GatewaySDK, 'getMasterCopies').mockImplementation(() =>
+        Promise.resolve([
+          {
+            address: '0xd9Db270c1B5E3Bd161E8c8503c55cEABeE709552',
+            version: '1.3.0',
+            deployer: 'Gnosis',
+            deployedBlockNumber: 12504268,
+            lastIndexedBlockNumber: 14927028,
+            l2: false,
+          },
+          {
+            address: '0x3E5c63644E683549055b9Be8653de26E0B4CD36E',
+            version: '1.3.0+L2',
+            deployer: 'Gnosis',
+            deployedBlockNumber: 12504423,
+            lastIndexedBlockNumber: 14927028,
+            l2: true,
+          },
+        ]),
+      )
+
+      const isValid = await isValidMasterCopy('1', '0x3E5c63644E683549055b9Be8653de26E0B4CD36E')
+      expect(isValid).toBe(true)
+    })
+  })
 })
diff --git a/src/logic/safe/utils/__tests__/shouldSafeStoreBeUpdated.test.ts b/src/logic/safe/utils/__tests__/shouldSafeStoreBeUpdated.test.ts
index 6b6a60787b..fd5ec47f99 100644
--- a/src/logic/safe/utils/__tests__/shouldSafeStoreBeUpdated.test.ts
+++ b/src/logic/safe/utils/__tests__/shouldSafeStoreBeUpdated.test.ts
@@ -35,6 +35,11 @@ const getMockedOldSafe = ({
       { tokenAddress: mockedActiveTokenAddress1, tokenBalance: '100' },
       { tokenAddress: mockedActiveTokenAddress2, tokenBalance: '10' },
     ],
+    implementation: {
+      value: '',
+      name: null,
+      logoUri: null,
+    },
     loaded: true,
     nonce: nonce || 2,
     recurringUser: recurringUser || false,
diff --git a/src/logic/safe/utils/safeVersion.ts b/src/logic/safe/utils/safeVersion.ts
index 0c853357f1..b3821d8864 100644
--- a/src/logic/safe/utils/safeVersion.ts
+++ b/src/logic/safe/utils/safeVersion.ts
@@ -1,13 +1,14 @@
 import semverLessThan from 'semver/functions/lt'
 import semverSatisfies from 'semver/functions/satisfies'
 import semverValid from 'semver/functions/valid'
-import { FEATURES } from '@gnosis.pm/safe-react-gateway-sdk'
+import { FEATURES, getMasterCopies } from '@gnosis.pm/safe-react-gateway-sdk'
 
 import { GnosisSafe } from 'src/types/contracts/gnosis_safe.d'
 import { getSafeMasterContract } from 'src/logic/contracts/safeContracts'
 import { LATEST_SAFE_VERSION } from 'src/utils/constants'
 import { Errors, logError } from 'src/logic/exceptions/CodedException'
 import { getChainInfo } from 'src/config'
+import { sameAddress } from 'src/logic/wallets/ethAddresses'
 
 const FEATURES_BY_VERSION: Record<string, string> = {
   [FEATURES.SAFE_TX_GAS_OPTIONAL]: '>=1.3.0',
@@ -86,3 +87,11 @@ export const getSafeVersionInfo = async (safeVersion: string): Promise<SafeVersi
     logError(Errors._606, err.message)
   }
 }
+
+export const isValidMasterCopy = async (chainId: string, masterCopyAddress: string): Promise<boolean> => {
+  const supportedMasterCopies = await getMasterCopies(chainId)
+
+  return supportedMasterCopies.some((supportedMasterCopy) =>
+    sameAddress(supportedMasterCopy.address, masterCopyAddress),
+  )
+}