diff --git a/smack-core/src/main/java/org/jivesoftware/smack/packet/DefaultExtensionElement.java b/smack-core/src/main/java/org/jivesoftware/smack/packet/DefaultExtensionElement.java
deleted file mode 100644
index 56090d568..000000000
--- a/smack-core/src/main/java/org/jivesoftware/smack/packet/DefaultExtensionElement.java
+++ /dev/null
@@ -1,138 +0,0 @@
-/**
- *
- * Copyright 2003-2007 Jive Software.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jivesoftware.smack.packet;
-
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-
-import org.jivesoftware.smack.util.XmlStringBuilder;
-
-/**
- * Default implementation of the ExtensionElement interface. Unless a ExtensionElementProvider
- * is registered with {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager},
- * instances of this class will be returned when getting stanza extensions.<p>
- *
- * This class provides a very simple representation of an XML sub-document. Each element
- * is a key in a Map with its CDATA being the value. For example, given the following
- * XML sub-document:
- *
- * <pre>
- * &lt;foo xmlns="http://bar.com"&gt;
- *     &lt;color&gt;blue&lt;/color&gt;
- *     &lt;food&gt;pizza&lt;/food&gt;
- * &lt;/foo&gt;</pre>
- *
- * In this case, getValue("color") would return "blue", and getValue("food") would
- * return "pizza". This parsing mechanism is very simplistic and will not work
- * as desired in all cases (for example, if some of the elements have attributes. In those
- * cases, a custom ExtensionElementProvider should be used.
- *
- * @author Matt Tucker
- * @deprecated use {@link org.jivesoftware.smack.packet.StandardExtensionElement} instead.
- */
-@Deprecated
-public class DefaultExtensionElement implements ExtensionElement {
-
-    private String elementName;
-    private String namespace;
-    private Map<String, String> map;
-
-    /**
-     * Creates a new generic stanza extension.
-     *
-     * @param elementName the name of the element of the XML sub-document.
-     * @param namespace the namespace of the element.
-     */
-    public DefaultExtensionElement(String elementName, String namespace) {
-        this.elementName = elementName;
-        this.namespace = namespace;
-    }
-
-     /**
-     * Returns the XML element name of the extension sub-packet root element.
-     *
-     * @return the XML element name of the stanza extension.
-     */
-    @Override
-    public String getElementName() {
-        return elementName;
-    }
-
-    /**
-     * Returns the XML namespace of the extension sub-packet root element.
-     *
-     * @return the XML namespace of the stanza extension.
-     */
-    @Override
-    public String getNamespace() {
-        return namespace;
-    }
-
-    @Override
-    public CharSequence toXML(org.jivesoftware.smack.packet.XmlEnvironment enclosingNamespace) {
-        XmlStringBuilder buf = new XmlStringBuilder();
-        buf.halfOpenElement(elementName).xmlnsAttribute(namespace).rightAngleBracket();
-        for (String name : getNames()) {
-            String value = getValue(name);
-            buf.element(name, value);
-        }
-        buf.closeElement(elementName);
-        return buf;
-    }
-
-    /**
-     * Returns an unmodifiable collection of the names that can be used to get
-     * values of the stanza extension.
-     *
-     * @return the names.
-     */
-    public synchronized Collection<String> getNames() {
-        if (map == null) {
-            return Collections.emptySet();
-        }
-        return Collections.unmodifiableSet(new HashMap<String, String>(map).keySet());
-    }
-
-    /**
-     * Returns a stanza extension value given a name.
-     *
-     * @param name the name.
-     * @return the value.
-     */
-    public synchronized String getValue(String name) {
-        if (map == null) {
-            return null;
-        }
-        return map.get(name);
-    }
-
-    /**
-     * Sets a stanza extension value using the given name.
-     *
-     * @param name the name.
-     * @param value the value.
-     */
-    public synchronized void setValue(String name, String value) {
-        if (map == null) {
-            map = new HashMap<String, String>();
-        }
-        map.put(name, value);
-    }
-}
diff --git a/smack-core/src/main/java/org/jivesoftware/smack/packet/Packet.java b/smack-core/src/main/java/org/jivesoftware/smack/packet/Packet.java
deleted file mode 100644
index 2a97d0eae..000000000
--- a/smack-core/src/main/java/org/jivesoftware/smack/packet/Packet.java
+++ /dev/null
@@ -1,229 +0,0 @@
-/**
- *
- * Copyright 2003-2007 Jive Software.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jivesoftware.smack.packet;
-
-import java.util.Collection;
-import java.util.List;
-import java.util.Set;
-
-/**
- * Deprecated interface of pre Smack 4.1 Stanzas.
- * @deprecated use {@link Stanza} instead
- */
-@Deprecated
-public interface Packet extends TopLevelStreamElement {
-
-    String TEXT = "text";
-    String ITEM = "item";
-
-    /**
-     * Returns the unique ID of the stanza. The returned value could be <code>null</code>.
-     *
-     * @return the packet's unique ID or <code>null</code> if the id is not available.
-     */
-    String getStanzaId();
-
-    /**
-     * Get the stanza id.
-     * @return the stanza id.
-     * @deprecated use {@link #getStanzaId()} instead.
-     */
-    @Deprecated
-    String getPacketID();
-
-    /**
-     * Sets the unique ID of the packet. To indicate that a stanza has no id
-     * pass <code>null</code> as the packet's id value.
-     *
-     * @param id the unique ID for the packet.
-     */
-    void setStanzaId(String id);
-
-    /**
-     * Set the stanza ID.
-     * @param packetID TODO javadoc me please
-     * @deprecated use {@link #setStanzaId(String)} instead.
-     */
-    @Deprecated
-    void setPacketID(String packetID);
-
-    /**
-     * Returns who the stanza is being sent "to", or <code>null</code> if
-     * the value is not set. The XMPP protocol often makes the "to"
-     * attribute optional, so it does not always need to be set.<p>
-     *
-     * @return who the stanza is being sent to, or <code>null</code> if the
-     *      value has not been set.
-     */
-    String getTo();
-
-    /**
-     * Sets who the stanza is being sent "to". The XMPP protocol often makes
-     * the "to" attribute optional, so it does not always need to be set.
-     *
-     * @param to who the stanza is being sent to.
-     */
-    void setTo(String to);
-
-    /**
-     * Returns who the stanza is being sent "from" or <code>null</code> if
-     * the value is not set. The XMPP protocol often makes the "from"
-     * attribute optional, so it does not always need to be set.<p>
-     *
-     * @return who the stanza is being sent from, or <code>null</code> if the
-     *      value has not been set.
-     */
-    String getFrom();
-
-    /**
-     * Sets who the stanza is being sent "from". The XMPP protocol often
-     * makes the "from" attribute optional, so it does not always need to
-     * be set.
-     *
-     * @param from who the stanza is being sent to.
-     */
-    void setFrom(String from);
-
-    /**
-     * Returns the error associated with this packet, or <code>null</code> if there are
-     * no errors.
-     *
-     * @return the error sub-packet or <code>null</code> if there isn't an error.
-     */
-    StanzaError getError();
-    /**
-     * Sets the error for this packet.
-     *
-     * @param error the error to associate with this packet.
-     */
-    void setError(StanzaError error);
-
-    @Override
-    String getLanguage();
-
-    /**
-     * Sets the xml:lang of this Stanza.
-     *
-     * @param language the xml:lang of this Stanza.
-     */
-    void setLanguage(String language);
-
-    /**
-     * Returns a copy of the stanza extensions attached to the packet.
-     *
-     * @return the stanza extensions.
-     */
-    List<ExtensionElement> getExtensions();
-
-    /**
-     * Return a set of all extensions with the given element name <i>and</i> namespace.
-     * <p>
-     * Changes to the returned set will update the stanza extensions, if the returned set is not the empty set.
-     * </p>
-     *
-     * @param elementName the element name, must not be null.
-     * @param namespace the namespace of the element(s), must not be null.
-     * @return a set of all matching extensions.
-     * @since 4.1
-     */
-    Set<ExtensionElement> getExtensions(String elementName, String namespace);
-
-    /**
-     * Returns the first extension of this stanza that has the given namespace.
-     * <p>
-     * When possible, use {@link #getExtension(String, String)} instead.
-     * </p>
-     *
-     * @param namespace the namespace of the extension that is desired.
-     * @return the stanza extension with the given namespace.
-     */
-    ExtensionElement getExtension(String namespace);
-
-    /**
-     * Returns the first stanza extension that matches the specified element name and
-     * namespace, or <code>null</code> if it doesn't exist. If the provided elementName is null,
-     * only the namespace is matched. Stanza extensions are
-     * are arbitrary XML sub-documents in standard XMPP packets. By default, a
-     * DefaultPacketExtension instance will be returned for each extension. However,
-     * PacketExtensionProvider instances can be registered with the
-     * {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager}
-     * class to handle custom parsing. In that case, the type of the Object
-     * will be determined by the provider.
-     *
-     * @param elementName the XML element name of the stanza extension. (May be null)
-     * @param namespace the XML element namespace of the stanza extension.
-     * @param <PE> type of the ExtensionElement.
-     * @return the extension, or <code>null</code> if it doesn't exist.
-     */
-    <PE extends ExtensionElement> PE getExtension(String elementName, String namespace);
-    /**
-     * Adds a stanza extension to the packet. Does nothing if extension is null.
-     *
-     * @param extension a stanza extension.
-     */
-    void addExtension(ExtensionElement extension);
-
-    /**
-     * Adds a collection of stanza extensions to the packet. Does nothing if extensions is null.
-     *
-     * @param extensions a collection of stanza extensions
-     */
-    void addExtensions(Collection<ExtensionElement> extensions);
-
-    /**
-     * Check if a stanza extension with the given element and namespace exists.
-     * <p>
-     * The argument <code>elementName</code> may be null.
-     * </p>
-     *
-     * @param elementName TODO javadoc me please
-     * @param namespace TODO javadoc me please
-     * @return true if a stanza extension exists, false otherwise.
-     */
-    boolean hasExtension(String elementName, String namespace);
-
-    /**
-     * Check if a stanza extension with the given namespace exists.
-     *
-     * @param namespace TODO javadoc me please
-     * @return true if a stanza extension exists, false otherwise.
-     */
-    boolean hasExtension(String namespace);
-
-    /**
-     * Remove the stanza extension with the given elementName and namespace.
-     *
-     * @param elementName TODO javadoc me please
-     * @param namespace TODO javadoc me please
-     * @return the removed stanza extension or null.
-     */
-    ExtensionElement removeExtension(String elementName, String namespace);
-
-    /**
-     * Removes a stanza extension from the packet.
-     *
-     * @param extension the stanza extension to remove.
-     * @return the removed stanza extension or null.
-     */
-    ExtensionElement removeExtension(ExtensionElement extension);
-
-    @Override
-    // NOTE When Smack is using Java 8, then this method should be moved in Element as "Default Method".
-    String toString();
-
-}
diff --git a/smack-core/src/main/java/org/jivesoftware/smack/packet/PacketExtension.java b/smack-core/src/main/java/org/jivesoftware/smack/packet/PacketExtension.java
deleted file mode 100644
index 04108ebb5..000000000
--- a/smack-core/src/main/java/org/jivesoftware/smack/packet/PacketExtension.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/**
- *
- * Copyright 2003-2007 Jive Software.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jivesoftware.smack.packet;
-
-/**
- * Interface to represent extension elements.
- * <p>
- * An extension element is an XML subdocument
- * with a root element name and namespace. Extension elements are used to provide
- * extended functionality beyond what is in the base XMPP specification. Examples of
- * extensions elements include message events, message properties, and extra presence data.
- * IQ stanzas have limited support for extension elements.
- * <p>
- * This class is used primarily for extended content in XMPP Stanzas, to act as so called "extension elements". For more
- * information see <a href="https://tools.ietf.org/html/rfc6120#section-8.4">RFC 6120 § 8.4 Extended Content</a>.
- * </p>
- *
- * @see DefaultExtensionElement
- * @see org.jivesoftware.smack.provider.ExtensionElementProvider
- * @author Matt Tucker
- * @deprecated use {@link ExtensionElement} instead.
- */
-@Deprecated
-public interface PacketExtension extends ExtensionElement {
-
-}