diff --git a/packages/desktop/src/renderer/components/CreateUsername/CreateUsername.test.tsx b/packages/desktop/src/renderer/components/CreateUsername/CreateUsername.test.tsx
index 61c479484f..e5b406d690 100644
--- a/packages/desktop/src/renderer/components/CreateUsername/CreateUsername.test.tsx
+++ b/packages/desktop/src/renderer/components/CreateUsername/CreateUsername.test.tsx
@@ -218,7 +218,7 @@ describe('Username taken', () => {
                         class="MuiTypography-root MuiTypography-caption css-1d4bzk2-MuiTypography-root"
                         style="margin-top: 8px;"
                       >
-                        Your username will be public, but you can choose any name you like. No spaces or special characters. Lowercase letters and numbers only.
+                        You can choose any username you like. No spaces or special characters.
                       </span>
                       <div
                         class="CreateUsernameComponent-gutter"
diff --git a/packages/desktop/src/renderer/components/CreateUsername/CreateUsernameComponent.tsx b/packages/desktop/src/renderer/components/CreateUsername/CreateUsernameComponent.tsx
index 01b51091e7..b8d9e64e94 100644
--- a/packages/desktop/src/renderer/components/CreateUsername/CreateUsernameComponent.tsx
+++ b/packages/desktop/src/renderer/components/CreateUsername/CreateUsernameComponent.tsx
@@ -210,8 +210,8 @@ export const CreateUsernameComponent: React.FC<CreateUsernameComponentProps> = (
     setUserName(parsedName)
     setParsedNameDiffers(name !== parsedName)
     if (registeredUsers && !isNewUser) {
-      const allUsersArr = Object.values(registeredUsers).map(user => user.username)
-      if (allUsersArr.includes(name)) {
+      const allUsersSet = new Set(Object.values(registeredUsers).map(user => user.username))
+      if (allUsersSet.has(name)) {
         setError('userName', { message: `${name} is already taken` })
       }
     }
@@ -301,8 +301,7 @@ export const CreateUsernameComponent: React.FC<CreateUsernameComponentProps> = (
 
                 {!isNewUser && (
                   <Typography variant='caption' style={{ marginTop: 8 }}>
-                    Your username will be public, but you can choose any name you like. No spaces or special characters.
-                    Lowercase letters and numbers only.
+                    You can choose any username you like. No spaces or special characters.
                   </Typography>
                 )}
                 <div className={classes.gutter}>
diff --git a/packages/mobile/src/components/Registration/UsernameRegistration.component.tsx b/packages/mobile/src/components/Registration/UsernameRegistration.component.tsx
index 44d3a1b5bb..7c0301ae07 100644
--- a/packages/mobile/src/components/Registration/UsernameRegistration.component.tsx
+++ b/packages/mobile/src/components/Registration/UsernameRegistration.component.tsx
@@ -48,8 +48,8 @@ export const UsernameRegistration: FC<UsernameRegistrationProps> = ({
     setUserName(parsedName)
     setParsedNameDiffers(name !== parsedName)
     if (registeredUsers && !isNewUser) {
-      const allUsersArr = Object.values(registeredUsers).map(user => user.username)
-      if (allUsersArr.includes(name)) {
+      const allUsersSet = new Set(Object.values(registeredUsers).map(user => user.username))
+      if (allUsersSet.has(name)) {
         setInputError(`Username @${name} is already taken`)
       }
     }
diff --git a/packages/state-manager/src/sagas/identity/identity.selectors.ts b/packages/state-manager/src/sagas/identity/identity.selectors.ts
index 43e6d44da4..9004adb288 100644
--- a/packages/state-manager/src/sagas/identity/identity.selectors.ts
+++ b/packages/state-manager/src/sagas/identity/identity.selectors.ts
@@ -26,6 +26,10 @@ export const communityMembership = createSelector(currentIdentity, identity => {
   return Boolean(identity?.userCsr)
 })
 
+export const hasCertificate = createSelector(currentIdentity, identity => {
+  return Boolean(identity?.userCertificate)
+})
+
 export const joinedCommunities = createSelector(selectCommunities, selectEntities, (communities, identities) => {
   return communities.filter(community => {
     return identities[community.id]?.userCertificate
@@ -45,9 +49,8 @@ export const usernameTaken = createSelector(currentIdentity, certificatesMapping
   const username = identity?.nickname
   if (!username) return false
 
-  const allUsernames: string[] = Object.values(certs).map(u => u.username)
-
-  if (allUsernames.includes(username)) {
+  const allUsersSet = new Set(Object.values(certs).map(user => user.username))
+  if (allUsersSet.has(username)) {
     return true
   }
 
@@ -63,4 +66,5 @@ export const identitySelectors = {
   joinTimestamp,
   csr,
   usernameTaken,
+  hasCertificate,
 }
diff --git a/packages/state-manager/src/sagas/identity/registerUsername/registerUsername.saga.test.ts b/packages/state-manager/src/sagas/identity/registerUsername/registerUsername.saga.test.ts
index da2c954b8b..f536ec15be 100644
--- a/packages/state-manager/src/sagas/identity/registerUsername/registerUsername.saga.test.ts
+++ b/packages/state-manager/src/sagas/identity/registerUsername/registerUsername.saga.test.ts
@@ -87,7 +87,7 @@ describe('registerUsernameSaga', () => {
       .run()
   })
 
-  it.only('username taken - use current CSR and new nickname', async () => {
+  it('username taken - use current CSR and new nickname', async () => {
     setupCrypto()
     const socket = { emit: jest.fn(), on: jest.fn() } as unknown as Socket
 
diff --git a/packages/state-manager/src/sagas/identity/updateCertificate/updateCertificate.saga.ts b/packages/state-manager/src/sagas/identity/updateCertificate/updateCertificate.saga.ts
index ca304e8e6a..a03438bd5d 100644
--- a/packages/state-manager/src/sagas/identity/updateCertificate/updateCertificate.saga.ts
+++ b/packages/state-manager/src/sagas/identity/updateCertificate/updateCertificate.saga.ts
@@ -2,12 +2,12 @@ import { SendCertificatesResponse } from '@quiet/types'
 import { PayloadAction } from '@reduxjs/toolkit'
 import { select, call, put } from 'typed-redux-saga'
 import { identitySelectors } from '../identity.selectors'
-import { CertFieldsTypes, getCertFieldValue, getReqFieldValue, loadCSR, parseCertificate } from '@quiet/identity'
+import { loadCSR, pubKeyMatch } from '@quiet/identity'
 import { identityActions } from '../identity.slice'
 import { communitiesSelectors } from '../../communities/communities.selectors'
 
 export function* updateCertificateSaga(action: PayloadAction<SendCertificatesResponse>): Generator {
-  const certificate = yield* select(identitySelectors.communityMembership)
+  const certificate = yield* select(identitySelectors.hasCertificate)
   const communityId = yield* select(communitiesSelectors.currentCommunityId)
 
   if (certificate) return
@@ -17,12 +17,9 @@ export function* updateCertificateSaga(action: PayloadAction<SendCertificatesRes
   if (!csr?.userCsr) return
 
   const parsedCsr = yield* call(loadCSR, csr?.userCsr)
-  const pubKey = getReqFieldValue(parsedCsr, CertFieldsTypes.dmPublicKey)
 
   const cert = action.payload.certificates.find(cert => {
-    const parsedCert = parseCertificate(cert)
-    const certPubKey = getCertFieldValue(parsedCert, CertFieldsTypes.dmPublicKey)
-    if (certPubKey === pubKey) return cert
+    if (pubKeyMatch(cert, parsedCsr)) return cert
   })
 
   if (cert) {