diff --git a/libdino/src/entity/jid.vala b/libdino/src/entity/jid.vala
index edd3bc91..2283b466 100644
--- a/libdino/src/entity/jid.vala
+++ b/libdino/src/entity/jid.vala
@@ -3,7 +3,7 @@ public class Dino.Entities.Jid : Object {
     public string domainpart { get; set; }
     public string? resourcepart { get; set; }
 
-    public Jid? bare_jid {
+    public Jid bare_jid {
         owned get { return localpart != null ? new Jid(@"$localpart@$domainpart") : new Jid(domainpart); }
     }
 
diff --git a/libdino/src/service/avatar_manager.vala b/libdino/src/service/avatar_manager.vala
index de3d86fb..42a08168 100644
--- a/libdino/src/service/avatar_manager.vala
+++ b/libdino/src/service/avatar_manager.vala
@@ -47,12 +47,16 @@ public class AvatarManager : StreamInteractionModule, Object {
     }
 
     private Pixbuf? get_avatar_by_hash(string hash) {
-        if (cached_pixbuf.has_key(hash)) {
-            return cached_pixbuf[hash];
+        lock (cached_pixbuf) {
+            if (cached_pixbuf.has_key(hash)) {
+                return cached_pixbuf[hash];
+            }
         }
         Pixbuf? image = avatar_storage.get_image(hash);
         if (image != null) {
-            cached_pixbuf[hash] = image;
+            lock (cached_pixbuf) {
+                cached_pixbuf[hash] = image;
+            }
         }
         return image;
     }
@@ -62,13 +66,17 @@ public class AvatarManager : StreamInteractionModule, Object {
         if (!stream_interactor.get_module(MucManager.IDENTITY).is_groupchat_occupant(jid, account)) {
             jid_ = jid.bare_jid;
         }
-        string? user_avatars_id = user_avatars[jid_];
-        if (user_avatars_id != null) {
-            return get_avatar_by_hash(user_avatars_id);
+        lock(user_avatars) {
+            string? user_avatars_id = user_avatars[jid_];
+            if (user_avatars_id != null) {
+                return get_avatar_by_hash(user_avatars_id);
+            }
         }
-        string? vcard_avatars_id = vcard_avatars[jid_];
-        if (vcard_avatars_id != null) {
-            return get_avatar_by_hash(vcard_avatars_id);
+        lock(vcard_avatars) {
+            string? vcard_avatars_id = vcard_avatars[jid_];
+            if (vcard_avatars_id != null) {
+                return get_avatar_by_hash(vcard_avatars_id);
+            }
         }
         return null;
     }
@@ -103,20 +111,26 @@ public class AvatarManager : StreamInteractionModule, Object {
             on_vcard_avatar_received(account, new Jid(jid), id)
         );
 
-        user_avatars = db.get_avatar_hashes(Source.USER_AVATARS);
-        foreach (Jid jid in user_avatars.keys) {
-            on_user_avatar_received(account, jid, user_avatars[jid]);
+        lock (user_avatars) {
+            user_avatars = db.get_avatar_hashes(Source.USER_AVATARS);
+            foreach (Jid jid in user_avatars.keys) {
+                on_user_avatar_received(account, jid, user_avatars[jid]);
+            }
         }
-        vcard_avatars = db.get_avatar_hashes(Source.VCARD);
-        foreach (Jid jid in vcard_avatars.keys) {
-            on_vcard_avatar_received(account, jid, vcard_avatars[jid]);
+        lock (vcard_avatars) {
+            vcard_avatars = db.get_avatar_hashes(Source.VCARD);
+            foreach (Jid jid in vcard_avatars.keys) {
+                on_vcard_avatar_received(account, jid, vcard_avatars[jid]);
+            }
         }
     }
 
     private void on_user_avatar_received(Account account, Jid jid, string id) {
-        if (!user_avatars.has_key(jid) || user_avatars[jid] != id) {
-            user_avatars[jid] = id;
-            db.set_avatar_hash(jid, id, Source.USER_AVATARS);
+        lock (user_avatars) {
+            if (!user_avatars.has_key(jid) || user_avatars[jid] != id) {
+                user_avatars[jid] = id;
+                db.set_avatar_hash(jid, id, Source.USER_AVATARS);
+            }
         }
         Pixbuf? avatar = avatar_storage.get_image(id);
         if (avatar != null) {
@@ -125,10 +139,12 @@ public class AvatarManager : StreamInteractionModule, Object {
     }
 
     private void on_vcard_avatar_received(Account account, Jid jid, string id) {
-        if (!vcard_avatars.has_key(jid) || vcard_avatars[jid] != id) {
-            vcard_avatars[jid] = id;
-            if (!jid.is_full()) { // don't save muc avatars
-                db.set_avatar_hash(jid, id, Source.VCARD);
+        lock (vcard_avatars) {
+            if (!vcard_avatars.has_key(jid) || vcard_avatars[jid] != id) {
+                vcard_avatars[jid] = id;
+                if (!jid.is_full()) { // don't save muc avatars
+                    db.set_avatar_hash(jid, id, Source.VCARD);
+                }
             }
         }
         Pixbuf? avatar = avatar_storage.get_image(id);
diff --git a/libdino/src/service/muc_manager.vala b/libdino/src/service/muc_manager.vala
index a0d6dbe5..3c855c0e 100644
--- a/libdino/src/service/muc_manager.vala
+++ b/libdino/src/service/muc_manager.vala
@@ -161,9 +161,8 @@ public class MucManager : StreamInteractionModule, Object {
         });
     }
 
-    private void on_stream_negotiated(Account account) {
-        Core.XmppStream stream = stream_interactor.get_stream(account);
-        if (stream != null) stream.get_module(Xep.Bookmarks.Module.IDENTITY).get_conferences(stream, (stream, conferences, o) => {
+    private void on_stream_negotiated(Account account, Core.XmppStream stream) {
+        stream.get_module(Xep.Bookmarks.Module.IDENTITY).get_conferences(stream, (stream, conferences, o) => {
             Tuple<MucManager, Account> tuple = o as Tuple<MucManager, Account>;
             MucManager outer_ = tuple.a;
             Account account_ = tuple.b;
diff --git a/libdino/src/service/stream_interactor.vala b/libdino/src/service/stream_interactor.vala
index 81ddfebd..028d031b 100644
--- a/libdino/src/service/stream_interactor.vala
+++ b/libdino/src/service/stream_interactor.vala
@@ -9,7 +9,7 @@ public class StreamInteractor {
 
     public signal void account_added(Account account);
     public signal void account_removed(Account account);
-    public signal void stream_negotiated(Account account);
+    public signal void stream_negotiated(Account account, Core.XmppStream stream);
 
     public ModuleManager module_manager;
     public ConnectionManager connection_manager;
@@ -59,7 +59,7 @@ public class StreamInteractor {
 
     private void on_stream_opened(Account account, Core.XmppStream stream) {
         stream.stream_negotiated.connect( (stream) => {
-            stream_negotiated(account);
+            stream_negotiated(account, stream);
         });
     }
 }
diff --git a/xmpp-vala/src/core/stanza_attribute.vala b/xmpp-vala/src/core/stanza_attribute.vala
index e6887f33..26e63f80 100644
--- a/xmpp-vala/src/core/stanza_attribute.vala
+++ b/xmpp-vala/src/core/stanza_attribute.vala
@@ -1,7 +1,18 @@
 namespace Xmpp.Core {
+
 public class StanzaAttribute : StanzaEntry {
 
-    public StanzaAttribute() {}
+    internal const string ATTRIBUTE_STRING_FORMAT = "{%s}:%s='%s'";
+    internal const string ATTRIBUTE_STRING_NO_NS_FORMAT = "%s='%s'";
+    internal const string ATTRIBUTE_STRING_ANSI_FORMAT = ANSI_COLOR_GRAY+"{%s}:"+ANSI_COLOR_END+"%s="+ANSI_COLOR_GREEN+"'%s'"+ANSI_COLOR_END;
+    internal const string ATTRIBUTE_STRING_ANSI_NO_NS_FORMAT = "%s="+ANSI_COLOR_GREEN+"'%s'"+ANSI_COLOR_END;
+    internal const string ATTRIBUTE_XML_FORMAT = "%s:%s='%s'";
+    internal const string ATTRIBUTE_XML_NO_NS_FORMAT = "%s='%s'";
+    internal const string ATTRIBUTE_XML_ANSI_FORMAT = "%s:%s="+ANSI_COLOR_GREEN+"'%s'"+ANSI_COLOR_END;
+    internal const string ATTRIBUTE_XML_ANSI_NO_NS_FORMAT = "%s="+ANSI_COLOR_GREEN+"'%s'"+ANSI_COLOR_END;
+
+    internal StanzaAttribute() {
+    }
 
     public StanzaAttribute.build(string ns_uri, string name, string val) {
         this.ns_uri = ns_uri;
@@ -9,29 +20,47 @@ public class StanzaAttribute : StanzaEntry {
         this.val = val;
     }
 
-    public string to_string() {
-        if (ns_uri == null) {
-            return @"$name='$val'";
+    internal string printf(string fmt, bool no_ns = false, string? ns_name = null) {
+        if (no_ns) {
+            return fmt.printf(name, (!)val);
         } else {
-            return @"{$ns_uri}:$name='$val'";
+            if (ns_name == null) {
+                return fmt.printf((!)ns_uri, name, (!)val);
+            } else {
+                return fmt.printf((!)ns_name, name, (!)val);
+            }
         }
     }
 
+    public string to_string() {
+        return printf(ATTRIBUTE_STRING_FORMAT);
+    }
+
     public string to_ansi_string(bool hide_ns = false) {
-        if (ns_uri == null || hide_ns) {
-            return @"$name=$ANSI_COLOR_GREEN'$val'$ANSI_COLOR_END";
+        if (hide_ns) {
+            return printf(ATTRIBUTE_STRING_ANSI_NO_NS_FORMAT, true);
         } else {
-            return @"$ANSI_COLOR_GRAY{$ns_uri}:$ANSI_COLOR_END$name=$ANSI_COLOR_GREEN'$val'$ANSI_COLOR_END";
+            return printf(ATTRIBUTE_STRING_ANSI_FORMAT);
         }
     }
 
-    public string to_xml(NamespaceState? state_) throws XmlError {
+    public string to_xml(NamespaceState? state_ = null) throws XmlError {
         NamespaceState state = state_ ?? new NamespaceState();
         if (ns_uri == state.current_ns_uri || (ns_uri == XMLNS_URI && name == "xmlns")) {
-            return @"$name='$val'";
+            return printf(ATTRIBUTE_XML_NO_NS_FORMAT, true);
         } else {
-            return "%s:%s='%s'".printf (state.find_name (ns_uri), name, val);
+            return printf(ATTRIBUTE_XML_FORMAT, false, state.find_name((!)ns_uri));
+        }
+    }
+
+    public string to_ansi_xml(NamespaceState? state_ = null) throws XmlError {
+        NamespaceState state = state_ ?? new NamespaceState();
+        if (ns_uri == state.current_ns_uri || (ns_uri == XMLNS_URI && name == "xmlns")) {
+            return printf(ATTRIBUTE_XML_ANSI_NO_NS_FORMAT, true);
+        } else {
+            return printf(ATTRIBUTE_XML_ANSI_FORMAT, false, state.find_name((!)ns_uri));
         }
     }
 }
+
 }
diff --git a/xmpp-vala/src/core/stanza_node.vala b/xmpp-vala/src/core/stanza_node.vala
index d9398a39..fd44c925 100644
--- a/xmpp-vala/src/core/stanza_node.vala
+++ b/xmpp-vala/src/core/stanza_node.vala
@@ -12,12 +12,17 @@ public abstract class StanzaEntry {
     public string name;
     public string? val;
 
-    public string encoded_val {
+    public string? encoded_val {
         owned get {
-            return val != null ? val.replace("&", "&amp;").replace("\"", "&quot;").replace("'", "&apos;").replace("<", "&lt;").replace(">", "&gt;") : null;
+            if (val == null) return null;
+            return ((!)val).replace("&", "&amp;").replace("\"", "&quot;").replace("'", "&apos;").replace("<", "&lt;").replace(">", "&gt;");
         }
         set {
-            string tmp = value.replace("&gt;", ">").replace("&lt;", "<").replace("&apos;","'").replace("&quot;","\"");
+            if (value == null) {
+                val = null;
+                return;
+            }
+            string tmp = ((!)value).replace("&gt;", ">").replace("&lt;", "<").replace("&apos;","'").replace("&quot;","\"");
             while (tmp.contains("&#")) {
                 int start = tmp.index_of("&#");
                 int end = tmp.index_of(";", start);
@@ -39,26 +44,20 @@ public abstract class StanzaEntry {
     }
 }
 
-public class NoStanza : StanzaEntry {
-    public NoStanza(string? name) {
-        this.name = name;
-    }
-}
-
 public class StanzaNode : StanzaEntry {
     public ArrayList<StanzaNode> sub_nodes = new ArrayList<StanzaNode>();
     public ArrayList<StanzaAttribute> attributes = new ArrayList<StanzaAttribute>();
     public bool has_nodes = false;
     public bool pseudo = false;
 
-    public StanzaNode() {
+    internal StanzaNode() {
     }
 
     public StanzaNode.build(string name, string ns_uri = "jabber:client", ArrayList<StanzaNode>? nodes = null, ArrayList<StanzaAttribute>? attrs = null) {
         this.ns_uri = ns_uri;
         this.name = name;
-        if (nodes != null) this.sub_nodes.add_all(nodes);
-        if (attrs != null) this.attributes.add_all(attrs);
+        if (nodes != null) this.sub_nodes.add_all((!)nodes);
+        if (attrs != null) this.attributes.add_all((!)attrs);
     }
 
     public StanzaNode.text(string text) {
@@ -72,7 +71,8 @@ public class StanzaNode : StanzaEntry {
     }
 
     public StanzaNode add_self_xmlns() {
-        return put_attribute("xmlns", ns_uri);
+        if (ns_uri == null) return this;
+        return put_attribute("xmlns", (!)ns_uri);
     }
 
     public unowned string? get_attribute(string name, string? ns_uri = null) {
@@ -88,7 +88,7 @@ public class StanzaNode : StanzaEntry {
             }
         }
         foreach (var attr in attributes) {
-            if (attr.ns_uri == _ns_uri && attr.name == _name) return attr.val;
+            if (attr.ns_uri == (!)_ns_uri && attr.name == _name) return attr.val;
         }
         return null;
     }
@@ -96,19 +96,19 @@ public class StanzaNode : StanzaEntry {
     public int get_attribute_int(string name, int def = -1, string? ns_uri = null) {
         string? res = get_attribute(name, ns_uri);
         if (res == null) return def;
-        return int.parse(res);
+        return int.parse((!)res);
     }
 
     public uint get_attribute_uint(string name, uint def = 0, string? ns_uri = null) {
         string? res = get_attribute(name, ns_uri);
         if (res == null) return def;
-        return (uint) long.parse(res);
+        return (uint) long.parse((!)res);
     }
 
     public bool get_attribute_bool(string name, bool def = false, string? ns_uri = null) {
         string? res = get_attribute(name, ns_uri);
         if (res == null) return def;
-        return res.down() == "true" || res == "1";
+        return ((!)res).down() == "true" || res == "1";
     }
 
     public StanzaAttribute? get_attribute_raw(string name, string? ns_uri = null) {
@@ -137,34 +137,26 @@ public class StanzaNode : StanzaEntry {
         return ret;
     }
 
-    public StanzaEntry get(...) {
-        va_list l = va_list();
-        StanzaEntry? res = get_deep_attribute_(va_list.copy(l));
-        if (res != null) return res;
-        res = get_deep_subnode_(va_list.copy(l));
-        if (res != null) return res;
-        return new NoStanza("-");
-    }
-
     public unowned string? get_deep_attribute(...) {
         va_list l = va_list();
-        var res = get_deep_attribute_(va_list.copy(l));
+        StanzaAttribute? res = get_deep_attribute_(va_list.copy(l));
         if (res == null) return null;
-        return res.val;
+        return ((!)res).val;
     }
 
     public StanzaAttribute? get_deep_attribute_(va_list l) {
-        StanzaNode? node = this;
+        StanzaNode node = this;
         string? attribute_name = l.arg();
         if (attribute_name == null) return null;
         while (true) {
             string? s = l.arg();
             if (s == null) break;
-            node = node.get_subnode(attribute_name);
-            if (node == null) return null;
+            StanzaNode? node_tmp = node.get_subnode((!)attribute_name);
+            if (node_tmp == null) return null;
+            node = (!)node_tmp;
             attribute_name = s;
         }
-        return node.get_attribute_raw(attribute_name);
+        return node.get_attribute_raw((!)attribute_name);
     }
 
     public StanzaNode? get_subnode(string name, string? ns_uri = null, bool recurse = false) {
@@ -217,35 +209,35 @@ public class StanzaNode : StanzaEntry {
     }
 
     public StanzaNode? get_deep_subnode_(va_list l) {
-        StanzaNode? node = this;
+        StanzaNode node = this;
         while (true) {
             string? s = l.arg();
             if (s == null) break;
-            node = node.get_subnode(s);
-            if (node == null) return null;
+            StanzaNode? node_tmp = node.get_subnode((!)s);
+            if (node_tmp == null) return null;
+            node = (!)node_tmp;
         }
         return node;
     }
 
     public ArrayList<StanzaNode> get_deep_subnodes(...) {
         va_list l = va_list();
-        var res = get_deep_subnodes_(va_list.copy(l));
-        if (res != null) return res;
-        return new ArrayList<StanzaNode>();
+        return get_deep_subnodes_(va_list.copy(l));
     }
 
     public ArrayList<StanzaNode> get_deep_subnodes_(va_list l) {
-        StanzaNode? node = this;
+        StanzaNode node = this;
         string? subnode_name = l.arg();
         if (subnode_name == null) return new ArrayList<StanzaNode>();
         while (true) {
             string? s = l.arg();
             if (s == null) break;
-            node = node.get_subnode(subnode_name);
-            if (node == null) return new ArrayList<StanzaNode>();
+            StanzaNode? node_tmp = node.get_subnode((!)subnode_name);
+            if (node_tmp == null) return new ArrayList<StanzaNode>();
+            node = (!)node_tmp;
             subnode_name = s;
         }
-        return node.get_subnodes(subnode_name);
+        return node.get_subnodes((!)subnode_name);
     }
 
     public ArrayList<StanzaNode> get_all_subnodes() {
@@ -255,7 +247,7 @@ public class StanzaNode : StanzaEntry {
     public ArrayList<StanzaNode> get_deep_all_subnodes(...) {
         va_list l = va_list();
         StanzaNode? node = get_deep_subnode_(va_list.copy(l));
-        if (node != null) return node.get_all_subnodes();
+        if (node != null) return ((!)node).get_all_subnodes();
         return new ArrayList<StanzaNode>();
     }
 
@@ -272,14 +264,16 @@ public class StanzaNode : StanzaEntry {
     public unowned string? get_deep_string_content(...) {
         va_list l = va_list();
         StanzaNode? node = get_deep_subnode_(va_list.copy(l));
-        if (node != null) return node.get_string_content();
+        if (node != null) return ((!)node).get_string_content();
         return null;
     }
 
     public StanzaNode put_attribute(string name, string val, string? ns_uri = null) {
-        if (name == "xmlns") ns_uri = XMLNS_URI;
-        if (ns_uri == null) ns_uri = this.ns_uri;
-        attributes.add(new StanzaAttribute.build(ns_uri, name, val));
+        string? _ns_uri = ns_uri;
+        if (name == "xmlns") _ns_uri = XMLNS_URI;
+        if (_ns_uri == null) _ns_uri = this.ns_uri;
+        if (_ns_uri == null) return this;
+        attributes.add(new StanzaAttribute.build((!)_ns_uri, name, val));
         return this;
     }
 
@@ -302,75 +296,79 @@ public class StanzaNode : StanzaEntry {
         return this;
     }
 
-    public string to_string(int i = 0) {
+    private const string TAG_START_BEGIN_FORMAT = "%s<{%s}:%s";
+    private const string TAG_START_EMPTY_END = " />\n";
+    private const string TAG_START_CONTENT_END = ">\n";
+    private const string TAG_END_FORMAT = "%s</{%s}:%s>\n";
+    private const string TAG_ANSI_START_BEGIN_FORMAT = "%s"+ANSI_COLOR_YELLOW+"<"+ANSI_COLOR_GRAY+"{%s}:"+ANSI_COLOR_YELLOW+"%s"+ANSI_COLOR_END;
+    private const string TAG_ANSI_START_BEGIN_NO_NS_FORMAT = "%s"+ANSI_COLOR_YELLOW+"<%s"+ANSI_COLOR_END;
+    private const string TAG_ANSI_START_EMPTY_END = ANSI_COLOR_YELLOW+" />"+ANSI_COLOR_END+"\n";
+    private const string TAG_ANSI_START_CONTENT_END = ANSI_COLOR_YELLOW+">"+ANSI_COLOR_END+"\n";
+    private const string TAG_ANSI_END_FORMAT = "%s"+ANSI_COLOR_YELLOW+"</"+ANSI_COLOR_GRAY+"{%s}:"+ANSI_COLOR_YELLOW+"%s>"+ANSI_COLOR_END+"\n";
+    private const string TAG_ANSI_END_NO_NS_FORMAT = "%s"+ANSI_COLOR_YELLOW+"</%s>"+ANSI_COLOR_END+"\n";
+
+    internal string printf(int i, string fmt_start_begin, string start_empty_end, string start_content_end, string fmt_end, string fmt_attr, bool no_ns = false) {
         string indent = string.nfill (i * 2, ' ');
         if (name == "#text") {
-            return @"$indent$val\n";
+            return indent + ((!)val).replace("\n", indent + "\n") + "\n";
         }
         var sb = new StringBuilder();
-        sb.append(@"$indent<{$ns_uri}:$name");
+        if (no_ns) {
+            sb.append_printf(fmt_start_begin, indent, name);
+        } else {
+            sb.append_printf(fmt_start_begin, indent, (!)ns_uri, name);
+        }
         foreach (StanzaAttribute attr in attributes) {
-            sb.append_printf(" %s", attr.to_string());
+            sb.append_printf(" %s", attr.printf(fmt_attr, no_ns));
         }
         if (!has_nodes && sub_nodes.size == 0) {
-            sb.append(" />\n");
+            sb.append(start_empty_end);
         } else {
-            sb.append(">\n");
+            sb.append(start_content_end);
             if (sub_nodes.size != 0) {
                 foreach (StanzaNode subnode in sub_nodes) {
-                    sb.append(subnode.to_string(i+1));
+                    sb.append(subnode.printf(i+1, fmt_start_begin, start_empty_end, start_content_end, fmt_end, fmt_attr, no_ns));
+                }
+                if (no_ns) {
+                    sb.append_printf(fmt_end, indent, name);
+                } else {
+                    sb.append_printf(fmt_end, indent, (!)ns_uri, name);
                 }
-                sb.append(@"$indent</{$ns_uri}:$name>\n");
             }
         }
         return sb.str;
     }
 
+    public string to_string(int i = 0) {
+        return printf(i, TAG_START_BEGIN_FORMAT, TAG_START_EMPTY_END, TAG_START_CONTENT_END, TAG_END_FORMAT, StanzaAttribute.ATTRIBUTE_STRING_FORMAT);
+    }
+
     public string to_ansi_string(bool hide_ns = false, int i = 0) {
-        string indent = string.nfill (i * 2, ' ');
-        if (name == "#text") {
-            return @"$indent$val\n";
-        }
-        var sb = new StringBuilder();
-        sb.append(@"$indent$ANSI_COLOR_YELLOW<");
-        if (!hide_ns) sb.append(@"$ANSI_COLOR_GRAY{$ns_uri}:$ANSI_COLOR_YELLOW");
-        sb.append(@"$name$ANSI_COLOR_END");
-        foreach (StanzaAttribute attr in attributes) {
-            sb.append_printf(" %s", attr.to_ansi_string(hide_ns));
-        }
-        if (!has_nodes && sub_nodes.size == 0) {
-            sb.append(@" $ANSI_COLOR_YELLOW/>$ANSI_COLOR_END\n");
+        if (hide_ns) {
+            return printf(i, TAG_ANSI_START_BEGIN_NO_NS_FORMAT, TAG_ANSI_START_EMPTY_END, TAG_ANSI_START_CONTENT_END, TAG_ANSI_END_NO_NS_FORMAT, StanzaAttribute.ATTRIBUTE_STRING_ANSI_NO_NS_FORMAT, true);
         } else {
-            sb.append(@"$ANSI_COLOR_YELLOW>$ANSI_COLOR_END\n");
-            if (sub_nodes.size != 0) {
-                foreach (StanzaNode subnode in sub_nodes) {
-                    sb.append(subnode.to_ansi_string(hide_ns, i + 1));
-                }
-                sb.append(@"$indent$ANSI_COLOR_YELLOW</");
-                if (!hide_ns) sb.append(@"$ANSI_COLOR_GRAY{$ns_uri}:$ANSI_COLOR_YELLOW");
-                sb.append(@"$name>$ANSI_COLOR_END\n");
-            }
+            return printf(i, TAG_ANSI_START_BEGIN_FORMAT, TAG_ANSI_START_EMPTY_END, TAG_ANSI_START_CONTENT_END, TAG_ANSI_END_FORMAT, StanzaAttribute.ATTRIBUTE_STRING_ANSI_FORMAT);
         }
-        return sb.str;
     }
 
     public string to_xml(NamespaceState? state = null) throws XmlError {
         NamespaceState my_state = state ?? new NamespaceState.for_stanza();
-        if (name == "#text") return @"$encoded_val";
+        if (name == "#text") return val == null ? "" : (!)encoded_val;
         foreach (var xmlns in get_attributes_by_ns_uri (XMLNS_URI)) {
+            if (xmlns.val == null) continue;
             if (xmlns.name == "xmlns") {
-                my_state = new NamespaceState.with_current(my_state, xmlns.val);
+                my_state = new NamespaceState.with_current(my_state, (!)xmlns.val);
             } else {
-                my_state = new NamespaceState.with_assoc(my_state, xmlns.val, xmlns.name);
+                my_state = new NamespaceState.with_assoc(my_state, (!)xmlns.val, xmlns.name);
             }
         }
         var sb = new StringBuilder();
         if (ns_uri == my_state.current_ns_uri) {
-            sb.append(@"<$name");
+            sb.append_printf("<%s", name);
         } else {
-            sb.append_printf("<%s:%s", my_state.find_name (ns_uri), name);
+            sb.append_printf("<%s:%s", my_state.find_name ((!)ns_uri), name);
         }
-        var attr_ns_state = new NamespaceState.with_current(my_state, ns_uri);
+        var attr_ns_state = new NamespaceState.with_current(my_state, (!)ns_uri);
         foreach (StanzaAttribute attr in attributes) {
             sb.append_printf(" %s", attr.to_xml(attr_ns_state));
         }
@@ -385,7 +383,7 @@ public class StanzaNode : StanzaEntry {
                 if (ns_uri == my_state.current_ns_uri) {
                     sb.append(@"</$name>");
                 } else {
-                    sb.append_printf("</%s:%s>", my_state.find_name (ns_uri), name);
+                    sb.append_printf("</%s:%s>", my_state.find_name ((!)ns_uri), name);
                 }
             }
         }
diff --git a/xmpp-vala/src/core/stanza_reader.vala b/xmpp-vala/src/core/stanza_reader.vala
index 0a90f855..f1ce5c19 100644
--- a/xmpp-vala/src/core/stanza_reader.vala
+++ b/xmpp-vala/src/core/stanza_reader.vala
@@ -44,9 +44,10 @@ public class StanzaReader {
 
     private void update_buffer() throws XmlError {
         try {
+            InputStream? input = this.input;
             if (input == null) throw new XmlError.EOF("No input stream specified and end of buffer reached.");
             if (cancellable.is_cancelled()) throw new XmlError.EOF("Input stream is canceled.");
-            buffer_fill = (int) input.read(buffer, cancellable);
+            buffer_fill = (int) ((!)input).read(buffer, cancellable);
             if (buffer_fill == 0) throw new XmlError.EOF("End of input stream reached.");
             buffer_pos = 0;
         } catch (GLib.IOError e) {
@@ -140,21 +141,21 @@ public class StanzaReader {
 
     private void handle_stanza_ns(StanzaNode res) throws XmlError {
         foreach (StanzaAttribute attr in res.attributes) {
-            if (attr.name == "xmlns") {
+            if (attr.name == "xmlns" && attr.val != null) {
                 attr.ns_uri = XMLNS_URI;
-                ns_state.set_current(attr.val);
-            } else if (attr.name.contains(":")) {
+                ns_state.set_current((!)attr.val);
+            } else if (attr.name.contains(":") && attr.val != null) {
                 var split = attr.name.split(":");
                 if (split[0] == "xmlns") {
                     attr.ns_uri = XMLNS_URI;
                     attr.name = split[1];
-                    ns_state.add_assoc(attr.val, attr.name);
+                    ns_state.add_assoc((!)attr.val, attr.name);
                 }
             }
         }
         handle_entry_ns(res);
         foreach (StanzaAttribute attr in res.attributes) {
-            handle_entry_ns(attr, res.ns_uri);
+            handle_entry_ns(attr, res.ns_uri ?? ns_state.current_ns_uri);
         }
     }
 
@@ -229,7 +230,7 @@ public class StanzaReader {
                         skip_single();
                         if (desc.contains(":")) {
                             var split = desc.split(":");
-                            assert(split[0] == ns_state.find_name(res.ns_uri));
+                            assert(split[0] == ns_state.find_name((!)res.ns_uri));
                             assert(split[1] == res.name);
                         } else {
                             assert(ns_state.current_ns_uri == res.ns_uri);
diff --git a/xmpp-vala/src/core/xmpp_stream.vala b/xmpp-vala/src/core/xmpp_stream.vala
index 684c7ed0..682639a8 100644
--- a/xmpp-vala/src/core/xmpp_stream.vala
+++ b/xmpp-vala/src/core/xmpp_stream.vala
@@ -65,7 +65,7 @@ public class XmppLog {
             }
             if (inner == null) return true;
             foreach (StanzaNode snode in node.get_all_subnodes()) {
-                if (inner.matches(snode)) return true;
+                if (((!)inner).matches(snode)) return true;
             }
             return false;
         }
@@ -78,10 +78,10 @@ public class XmppLog {
     private ArrayList<NodeLogDesc> descs = new ArrayList<NodeLogDesc>();
 
     public XmppLog(string? ident = null, string? desc = null) {
-        this.ident = ident;
-        this.desc = desc;
+        this.ident = ident ?? "";
+        this.desc = desc ?? "";
         this.use_ansi = is_atty(stderr.fileno());
-        while (this.desc != null && this.desc.contains(";")) {
+        while (this.desc.contains(";")) {
             string opt = this.desc.substring(0, this.desc.index_of(";"));
             this.desc = this.desc.substring(opt.length + 1);
             switch (opt) {
@@ -91,7 +91,7 @@ public class XmppLog {
                 case "show-ns": hide_ns = false; break;
             }
         }
-        if (desc != null) {
+        if (desc != "") {
             foreach (string d in this.desc.split("|")) {
                 descs.add(new NodeLogDesc(d));
             }
@@ -99,7 +99,7 @@ public class XmppLog {
     }
 
     public virtual bool should_log_node(StanzaNode node) {
-        if (ident == null || desc == null) return false;
+        if (ident == "" || desc == "") return false;
         if (desc == "all") return true;
         foreach (var desc in descs) {
             if (desc.matches(node)) return true;
@@ -108,7 +108,7 @@ public class XmppLog {
     }
 
     public virtual bool should_log_str(string str) {
-        if (ident == null || desc == null) return false;
+        if (ident == "" || desc == "") return false;
         if (desc == "all") return true;
         foreach (var desc in descs) {
             if (desc.name == "#text") return true;
@@ -158,12 +158,12 @@ public class XmppStream {
     public signal void stream_negotiated(XmppStream stream);
 
     public void connect(string? remote_name = null) throws IOStreamError {
-        if (remote_name != null) this.remote_name = remote_name;
+        if (remote_name != null) this.remote_name = (!)remote_name;
         SocketClient client = new SocketClient();
         try {
             SocketConnection? stream = client.connect(new NetworkService("xmpp-client", "tcp", this.remote_name));
             if (stream == null) throw new IOStreamError.CONNECT("client.connect() returned null");
-            reset_stream(stream);
+            reset_stream((!)stream);
         } catch (Error e) {
             stderr.printf("CONNECTION LOST?\n");
             throw new IOStreamError.CONNECT(e.message);
@@ -172,11 +172,14 @@ public class XmppStream {
     }
 
     public void disconnect() throws IOStreamError {
-        if (writer == null) throw new IOStreamError.DISCONNECT("trying to disconnect, but no stream open");
+        StanzaWriter? writer = this.writer;
+        StanzaReader? reader = this.reader;
+        IOStream? stream = this.stream;
+        if (writer == null || reader == null || stream == null) throw new IOStreamError.DISCONNECT("trying to disconnect, but no stream open");
         log.str("OUT", "</stream:stream>");
-        writer.write.begin("</stream:stream>");
-        reader.cancel();
-        stream.close_async.begin();
+        ((!)writer).write.begin("</stream:stream>");
+        ((!)reader).cancel();
+        ((!)stream).close_async.begin();
     }
 
     public void reset_stream(IOStream stream) {
@@ -195,9 +198,10 @@ public class XmppStream {
     }
 
     public StanzaNode read() throws IOStreamError {
+        StanzaReader? reader = this.reader;
         if (reader == null) throw new IOStreamError.READ("trying to read, but no stream open");
         try {
-            StanzaNode node = reader.read_node();
+            StanzaNode node = ((!)reader).read_node();
             log.node("IN", node);
             return node;
         } catch (XmlError e) {
@@ -206,10 +210,11 @@ public class XmppStream {
     }
 
     public void write(StanzaNode node) throws IOStreamError {
+        StanzaWriter? writer = this.writer;
         if (writer == null) throw new IOStreamError.WRITE("trying to write, but no stream open");
         try {
             log.node("OUT", node);
-            writer.write_node(node);
+            ((!)writer).write_node(node);
         } catch (XmlError e) {
             throw new IOStreamError.WRITE(e.message);
         }
@@ -230,7 +235,7 @@ public class XmppStream {
     public T? get_flag<T>(FlagIdentity<T>? identity) {
         if (identity == null) return null;
         foreach (var flag in flags) {
-            if (identity.matches(flag)) return identity.cast(flag);
+            if (((!)identity).matches(flag)) return ((!)identity).cast(flag);
         }
         return null;
     }
@@ -254,7 +259,7 @@ public class XmppStream {
     public T? get_module<T>(ModuleIdentity<T>? identity) {
         if (identity == null) return null;
         foreach (var module in modules) {
-            if (identity.matches(module)) return identity.cast(module);
+            if (((!)identity).matches(module)) return ((!)identity).cast(module);
         }
         return null;
     }
@@ -315,10 +320,10 @@ public class XmppStream {
             bool mandatory_outstanding = false;
             bool negotiation_active = false;
             foreach (XmppStreamModule module in modules) {
-                XmppStreamNegotiationModule negotiation_module = module as XmppStreamNegotiationModule;
+                XmppStreamNegotiationModule? negotiation_module = module as XmppStreamNegotiationModule;
                 if (negotiation_module != null) {
-                    if (negotiation_module.negotiation_active(this)) negotiation_active = true;
-                    if (negotiation_module.mandatory_outstanding(this)) mandatory_outstanding = true;
+                    if (((!)negotiation_module).negotiation_active(this)) negotiation_active = true;
+                    if (((!)negotiation_module).mandatory_outstanding(this)) mandatory_outstanding = true;
                 }
             }
             if (!negotiation_active) {
@@ -341,8 +346,10 @@ public class XmppStream {
     }
 
     private StanzaNode read_root() throws IOStreamError {
+        StanzaReader? reader = this.reader;
+        if (reader == null) throw new IOStreamError.READ("trying to read, but no stream open");
         try {
-            StanzaNode node = reader.read_root_node();
+            StanzaNode node = ((!)reader).read_root_node();
             log.node("IN ROOT", node);
             return node;
         } catch (XmlError e) {
diff --git a/xmpp-vala/src/module/util.vala b/xmpp-vala/src/module/util.vala
index 9096ea32..a0621225 100644
--- a/xmpp-vala/src/module/util.vala
+++ b/xmpp-vala/src/module/util.vala
@@ -1,5 +1,5 @@
 namespace Xmpp {
-    public string? get_bare_jid(string jid) {
+    public string get_bare_jid(string jid) {
         return jid.split("/")[0];
     }
 
diff --git a/xmpp-vala/src/module/xep/0045_muc/module.vala b/xmpp-vala/src/module/xep/0045_muc/module.vala
index 714bb2ca..badb7d60 100644
--- a/xmpp-vala/src/module/xep/0045_muc/module.vala
+++ b/xmpp-vala/src/module/xep/0045_muc/module.vala
@@ -167,16 +167,16 @@ public class Module : XmppStreamModule {
                         flag.finish_muc_enter(bare_jid, get_resource_part(presence.from));
                     }
                 }
-                string? affiliation = x_node["item", "affiliation"].val;
+                string? affiliation = x_node.get_deep_attribute("item", "affiliation");
                 if (affiliation != null) {
                     received_occupant_affiliation(stream, presence.from, affiliation);
                 }
-                string? jid = x_node["item", "jid"].val;
+                string? jid = x_node.get_deep_attribute("item", "jid");
                 if (jid != null) {
                     flag.set_real_jid(presence.from, jid);
                     received_occupant_jid(stream, presence.from, jid);
                 }
-                string? role = x_node["item", "role"].val;
+                string? role = x_node.get_deep_attribute("item", "role");
                 if (role != null) {
                     received_occupant_role(stream, presence.from, role);
                 }
diff --git a/xmpp-vala/src/module/xep/0048_bookmarks/module.vala b/xmpp-vala/src/module/xep/0048_bookmarks/module.vala
index 5170c80a..0e0d9489 100644
--- a/xmpp-vala/src/module/xep/0048_bookmarks/module.vala
+++ b/xmpp-vala/src/module/xep/0048_bookmarks/module.vala
@@ -77,7 +77,7 @@ public class Module : XmppStreamModule {
     public override void detach(XmppStream stream) { }
 
     public static void require(XmppStream stream) {
-        if (stream.get_module(IDENTITY) == null) stderr.printf("");
+        if (stream.get_module(IDENTITY) == null) stream.add_module(new Module());
     }
 
     public override string get_ns() { return NS_URI; }