diff --git a/libdino/src/entity/account.vala b/libdino/src/entity/account.vala
index 59a76c7d..23544b46 100644
--- a/libdino/src/entity/account.vala
+++ b/libdino/src/entity/account.vala
@@ -15,6 +15,7 @@ public class Account : Object {
     }
     public string? alias { get; set; }
     public bool enabled { get; set; default = false; }
+    public string? roster_version { get; set; }
 
     private Database? db;
 
@@ -34,6 +35,7 @@ public class Account : Object {
         password = row[db.account.password];
         alias = row[db.account.alias];
         enabled = row[db.account.enabled];
+        roster_version = row[db.account.roster_version];
 
         notify.connect(on_update);
     }
@@ -46,6 +48,7 @@ public class Account : Object {
                 .value(db.account.password, password)
                 .value(db.account.alias, alias)
                 .value(db.account.enabled, enabled)
+                .value(db.account.roster_version, roster_version)
                 .perform();
 
         notify.connect(on_update);
@@ -83,6 +86,8 @@ public class Account : Object {
                 update.set(db.account.alias, alias); break;
             case "enabled":
                 update.set(db.account.enabled, enabled); break;
+            case "roster-version":
+                update.set(db.account.roster_version, roster_version); break;
         }
         update.perform();
     }
diff --git a/libdino/src/service/database.vala b/libdino/src/service/database.vala
index 2836751f..19ca0b06 100644
--- a/libdino/src/service/database.vala
+++ b/libdino/src/service/database.vala
@@ -6,7 +6,7 @@ using Dino.Entities;
 namespace Dino {
 
 public class Database : Qlite.Database {
-    private const int VERSION = 1;
+    private const int VERSION = 2;
 
     public class AccountTable : Table {
         public Column<int> id = new Column.Integer("id") { primary_key = true, auto_increment = true };
@@ -15,10 +15,11 @@ public class Database : Qlite.Database {
         public Column<string> password = new Column.Text("password");
         public Column<string> alias = new Column.Text("alias");
         public Column<bool> enabled = new Column.BoolInt("enabled");
+        public Column<string> roster_version = new Column.Text("roster_version") { min_version=2 };
 
         internal AccountTable(Database db) {
             base(db, "account");
-            init({id, bare_jid, resourcepart, password, alias, enabled});
+            init({id, bare_jid, resourcepart, password, alias, enabled, roster_version});
         }
     }
 
@@ -128,18 +129,6 @@ public class Database : Qlite.Database {
         }
     }
 
-    public class AccountKeyValueTable : Table {
-        public Column<int> account_id = new Column.Integer("account_id");
-        public Column<string> key = new Column.Text("key");
-        public Column<string> value = new Column.Text("value");
-
-        internal AccountKeyValueTable(Database db) {
-            base(db, "account_key_value");
-            init({account_id, key, value});
-            unique({account_id, key}, "IGNORE");
-        }
-    }
-
     public AccountTable account { get; private set; }
     public JidTable jid { get; private set; }
     public MessageTable message { get; private set; }
@@ -148,7 +137,6 @@ public class Database : Qlite.Database {
     public AvatarTable avatar { get; private set; }
     public EntityFeatureTable entity_feature { get; private set; }
     public RosterTable roster { get; private set; }
-    public AccountKeyValueTable account_key_value { get; private set; }
 
     public Map<int, string> jid_table_cache = new HashMap<int, string>();
     public Map<string, int> jid_table_reverse = new HashMap<string, int>();
@@ -164,8 +152,7 @@ public class Database : Qlite.Database {
         avatar = new AvatarTable(this);
         entity_feature = new EntityFeatureTable(this);
         roster = new RosterTable(this);
-        account_key_value = new AccountKeyValueTable(this);
-        init({ account, jid, message, real_jid, conversation, avatar, entity_feature, roster, account_key_value });
+        init({ account, jid, message, real_jid, conversation, avatar, entity_feature, roster });
         exec("PRAGMA synchronous=0");
     }
 
diff --git a/libdino/src/service/roster_manager.vala b/libdino/src/service/roster_manager.vala
index 91da7579..e17c24e3 100644
--- a/libdino/src/service/roster_manager.vala
+++ b/libdino/src/service/roster_manager.vala
@@ -72,14 +72,12 @@ public class RosterStoreImpl : Roster.Storage, Object {
     private Account account;
     private Database db;
 
-    private string version = "";
     private HashMap<string, Roster.Item> items = new HashMap<string, Roster.Item>();
 
     public class RosterStoreImpl(Account account, Database db) {
         this.account = account;
         this.db = db;
 
-        version = db_get_roster_version() ?? "";
         foreach (Qlite.Row row in db.roster.select().with(db.roster.account_id, "=", account.id)) {
             Roster.Item item = new Roster.Item();
             item.jid = row[db.roster.jid];
@@ -90,7 +88,7 @@ public class RosterStoreImpl : Roster.Storage, Object {
     }
 
     public string? get_roster_version() {
-        return version;
+        return account.roster_version;
     }
 
     public Collection<Roster.Item> get_roster() {
@@ -102,11 +100,7 @@ public class RosterStoreImpl : Roster.Storage, Object {
     }
 
     public void set_roster_version(string version) {
-        db.account_key_value.insert().or("REPLACE")
-            .value(db.account_key_value.account_id, account.id)
-            .value(db.account_key_value.key, "roster_version")
-            .value(db.account_key_value.value, version)
-            .perform();
+        account.roster_version = version;
     }
 
     public void set_roster(Collection<Roster.Item> items) {
@@ -130,15 +124,7 @@ public class RosterStoreImpl : Roster.Storage, Object {
         items.unset(item.jid);
         db.roster.delete()
             .with(db.roster.account_id, "=", account.id)
-            .with(db.roster.jid, "=", item.jid);
-    }
-
-    private string? db_get_roster_version() {
-        Qlite.Row? row =  db.account_key_value.select()
-            .with(db.account_key_value.account_id, "=", account.id)
-            .with(db.account_key_value.key, "=", "roster_version").iterator().get_next();
-        if (row != null) return row[db.account_key_value.value];
-        return null;
+            .with(db.roster.jid, "=", item.jid).perform();
     }
 }
 
diff --git a/main/src/ui/chat_input/view.vala b/main/src/ui/chat_input/view.vala
index 3c5baa41..0887de25 100644
--- a/main/src/ui/chat_input/view.vala
+++ b/main/src/ui/chat_input/view.vala
@@ -61,6 +61,10 @@ public class View : Box {
                 case "/nick":
                     stream_interactor.get_module(MucManager.IDENTITY).change_nick(conversation.account, conversation.counterpart, token[1]);
                     break;
+                case "/ping":
+                    Xmpp.Core.XmppStream? stream = stream_interactor.get_stream(conversation.account);
+                    stream.get_module(Xmpp.Xep.Ping.Module.IDENTITY).send_ping(stream, conversation.counterpart.to_string() + "/" + token[1], null);
+                    break;
                 case "/topic":
                     stream_interactor.get_module(MucManager.IDENTITY).change_subject(conversation.account, conversation.counterpart, token[1]);
                     break;
diff --git a/xmpp-vala/src/module/xep/0199_ping.vala b/xmpp-vala/src/module/xep/0199_ping.vala
index 3b11bd73..6cb3b4ba 100644
--- a/xmpp-vala/src/module/xep/0199_ping.vala
+++ b/xmpp-vala/src/module/xep/0199_ping.vala
@@ -8,7 +8,7 @@ namespace Xmpp.Xep.Ping {
     public class Module : XmppStreamModule {
         public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, "0199_ping");
 
-        public void send_ping(XmppStream stream, string jid, ResponseListener listener) {
+        public void send_ping(XmppStream stream, string jid, ResponseListener? listener) {
             Iq.Stanza iq = new Iq.Stanza.get(new StanzaNode.build("ping", NS_URI).add_self_xmlns());
             iq.to = jid;
             stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, on_ping_response, listener);
@@ -35,9 +35,9 @@ namespace Xmpp.Xep.Ping {
             public void on_iq_set(XmppStream stream, Iq.Stanza iq) { }
         }
 
-        private static void on_ping_response(XmppStream stream, Iq.Stanza iq, Object o) {
-            ResponseListener listener = o as ResponseListener;
-            listener.on_result(stream);
+        private static void on_ping_response(XmppStream stream, Iq.Stanza iq, Object? o) {
+            ResponseListener? listener = o as ResponseListener;
+            if (listener != null) listener.on_result(stream);
         }
     }