diff --git a/AnotherIM/View/StartScreen.swift b/AnotherIM/View/StartScreen.swift
index abb84b9..1c0028f 100644
--- a/AnotherIM/View/StartScreen.swift
+++ b/AnotherIM/View/StartScreen.swift
@@ -79,12 +79,18 @@ struct StartScreen: View {
     }
 }
 
-final class TestStorage: XMPPClientStorageProtocol {
-    func updateCredentialsByUUID(_ uuid: UUID, _ credentials: XMPPClientCredentials) async {
-        print(uuid, credentials)
+final class TestStorage: XMPPStorage {
+    private var rosterVer: [String: String] = [:]
+
+    func getRosterVersion(jid: JID) async -> String? {
+        rosterVer[jid.bare]
     }
 
-    func getCredentialsByUUID(_ uuid: UUID) async -> XMPPClientCredentials? {
+    func setRosterVersion(jid: JID, ver: String) async {
+        rosterVer[jid.bare] = ver
+    }
+
+    func getCredentialsByUUID(_ uuid: UUID) async -> Credentials? {
         print(uuid)
         return ["password": pass]
     }
diff --git a/AnotherIM/xmpp/XMPPClient.swift b/AnotherIM/xmpp/XMPPClient.swift
index c82353a..157a835 100644
--- a/AnotherIM/xmpp/XMPPClient.swift
+++ b/AnotherIM/xmpp/XMPPClient.swift
@@ -92,7 +92,7 @@ struct ClientState: Codable & Equatable {
 final class XMPPClient {
     private var state = ClientState.initial
     private let logger = ClientLogger()
-    private let storage: XMPPClientStorageProtocol
+    private let storage: XMPPStorage
     private lazy var modules: [any XmppModule] = [
         SRVResolverModule(),
         ConnectionModule(self.fire),
@@ -104,7 +104,7 @@ final class XMPPClient {
         RosterModule()
     ]
 
-    init(storage: any XMPPClientStorageProtocol, userAgent: UserAgent) {
+    init(storage: any XMPPStorage, userAgent: UserAgent) {
         self.storage = storage
         state.userAgent = userAgent
     }
diff --git a/AnotherIM/xmpp/XMPPClientStorageProtocol.swift b/AnotherIM/xmpp/XMPPClientStorageProtocol.swift
deleted file mode 100644
index 2630c2e..0000000
--- a/AnotherIM/xmpp/XMPPClientStorageProtocol.swift
+++ /dev/null
@@ -1,22 +0,0 @@
-import Foundation
-
-typealias XMPPClientStorageProtocol =
-    AnyObject &
-    XMPPClientStorageCredentials &
-    XMPPClientStorageHistory
-
-// For storing credentials
-typealias XMPPClientCredentials = [String: String]
-protocol XMPPClientStorageCredentials: AnyObject {
-    func updateCredentialsByUUID(_ uuid: UUID, _ credentials: XMPPClientCredentials) async
-    func getCredentialsByUUID(_ uuid: UUID) async -> XMPPClientCredentials?
-}
-
-// For storing stanza history
-protocol XMPPClientStorageHistory:
-    XMPPClientStorageHistoryIqs &
-    XMPPClientStorageHistoryMessages &
-    XMPPClientStorageHistoryPresences {}
-protocol XMPPClientStorageHistoryIqs: AnyObject {}
-protocol XMPPClientStorageHistoryMessages: AnyObject {}
-protocol XMPPClientStorageHistoryPresences: AnyObject {}
diff --git a/AnotherIM/xmpp/XMPPStorage.swift b/AnotherIM/xmpp/XMPPStorage.swift
new file mode 100644
index 0000000..e3bca87
--- /dev/null
+++ b/AnotherIM/xmpp/XMPPStorage.swift
@@ -0,0 +1,18 @@
+import Foundation
+
+typealias Credentials = [String: String]
+
+protocol XMPPStorage: AnyObject {
+    // credentials
+    func getCredentialsByUUID(_ uuid: UUID) async -> Credentials?
+
+    // roster
+    func getRosterVersion(jid: JID) async -> String?
+    func setRosterVersion(jid: JID, ver: String) async
+
+    // messages
+
+    // omemo
+
+    // whatever else
+}
diff --git a/AnotherIM/xmpp/modules/auth/AuthorizationMechanisms.swift b/AnotherIM/xmpp/modules/auth/AuthorizationMechanisms.swift
index 1fbe224..7a83e98 100644
--- a/AnotherIM/xmpp/modules/auth/AuthorizationMechanisms.swift
+++ b/AnotherIM/xmpp/modules/auth/AuthorizationMechanisms.swift
@@ -42,7 +42,7 @@ protocol AuthorizationMechanism {
 final class AuthorizationMechanismImpl: AuthorizationMechanism {
     private let type: AuthorizationMechanismType
     private let jid: JID
-    private let credentials: XMPPClientCredentials?
+    private let credentials: Credentials?
     private let userAgent: UserAgent
     private let saslType: SaslType
     private let channelBind: String?
@@ -52,7 +52,7 @@ final class AuthorizationMechanismImpl: AuthorizationMechanism {
     private var clientNonce = ""
     private var serverSignature = ""
 
-    init(type: AuthorizationMechanismType, jid: JID, credentials: XMPPClientCredentials?, saslType: SaslType, userAgent: UserAgent, channelBind: String?, inlines: XMLElement?) {
+    init(type: AuthorizationMechanismType, jid: JID, credentials: Credentials?, saslType: SaslType, userAgent: UserAgent, channelBind: String?, inlines: XMLElement?) {
         self.type = type
         self.jid = jid
         self.credentials = credentials
diff --git a/AnotherIM/xmpp/modules/auth/AuthorizationModule.swift b/AnotherIM/xmpp/modules/auth/AuthorizationModule.swift
index d43c98b..7624e97 100644
--- a/AnotherIM/xmpp/modules/auth/AuthorizationModule.swift
+++ b/AnotherIM/xmpp/modules/auth/AuthorizationModule.swift
@@ -17,10 +17,10 @@ enum AuthorizationError: Error {
 final class AuthorizationModule: XmppModule {
     let id = "Authorization module"
 
-    private weak var storage: (any XMPPClientStorageCredentials)?
+    private weak var storage: (any XMPPStorage)?
     private var mechanism: AuthorizationMechanism?
 
-    init(_ storage: any XMPPClientStorageCredentials) {
+    init(_ storage: any XMPPStorage) {
         self.storage = storage
     }
 
@@ -79,7 +79,7 @@ private extension AuthorizationModule {
         ["tls-exporter", "tls-server-end-point"]
     }
 
-    func selectBestAuthMechanism(_ xml: XMLElement, _ isPlainAllowed: Bool, _ state: ClientState, _ creds: XMPPClientCredentials?) async -> Event {
+    func selectBestAuthMechanism(_ xml: XMLElement, _ isPlainAllowed: Bool, _ state: ClientState, _ creds: Credentials?) async -> Event {
         await withCheckedContinuation { continuation in
             var sasl1: [AuthorizationMechanismType] = []
             var channelBindings: [String] = []
diff --git a/AnotherIM/xmpp/modules/stanza/StanzaModule.swift b/AnotherIM/xmpp/modules/stanza/StanzaModule.swift
index d5fa365..5ae723f 100644
--- a/AnotherIM/xmpp/modules/stanza/StanzaModule.swift
+++ b/AnotherIM/xmpp/modules/stanza/StanzaModule.swift
@@ -3,9 +3,9 @@ import Foundation
 final class StanzaModule: XmppModule {
     let id = "Stanza module"
 
-    private weak var storage: XMPPClientStorageHistory?
+    private weak var storage: XMPPStorage?
 
-    init(_ storage: any XMPPClientStorageHistory) {
+    init(_ storage: any XMPPStorage) {
         self.storage = storage
     }
 
@@ -43,6 +43,7 @@ final class StanzaModule: XmppModule {
 // MARK: Save history
 private extension StanzaModule {
     func saveStanza(_ state: ClientState, _ stanza: Stanza, inbound: Bool) async {
+        guard let storage else { return }
         print(state, stanza, inbound)
     }
 }