diff --git a/libdevcore/Common.cpp b/libdevcore/Common.cpp
index 551b7af87..8a8687bfa 100644
--- a/libdevcore/Common.cpp
+++ b/libdevcore/Common.cpp
@@ -27,7 +27,7 @@ using namespace dev;
 namespace dev
 {
 
-char const* Version = "0.6.11";
+char const* Version = "0.7.0";
 
 }
 
diff --git a/libethcore/CommonEth.cpp b/libethcore/CommonEth.cpp
index 44297e0ba..1526da1b0 100644
--- a/libethcore/CommonEth.cpp
+++ b/libethcore/CommonEth.cpp
@@ -34,7 +34,7 @@ namespace dev
 namespace eth
 {
 
-const unsigned c_protocolVersion = 33;
+const unsigned c_protocolVersion = 34;
 const unsigned c_databaseVersion = 2;
 
 static const vector<pair<u256, string>> g_units =
diff --git a/libethereum/EthereumPeer.h b/libethereum/EthereumPeer.h
index 00788d019..bad12d3b7 100644
--- a/libethereum/EthereumPeer.h
+++ b/libethereum/EthereumPeer.h
@@ -58,6 +58,9 @@ public:
 	/// What is our name?
 	static std::string name() { return "eth"; }
 
+	/// What is our version?
+	static u256 version() { return c_protocolVersion; }
+
 	/// What is the ethereum subprotocol host object.
 	EthereumHost* host() const;
 
diff --git a/libp2p/Capability.h b/libp2p/Capability.h
index bffd38c79..00cccaeef 100644
--- a/libp2p/Capability.h
+++ b/libp2p/Capability.h
@@ -39,6 +39,7 @@ public:
 
 	/// Must return the capability name.
 	static std::string name() { return ""; }
+	static u256 version() { return 0; }
 
 	Session* session() const { return m_session; }
 	HostCapabilityFace* hostCapability() const { return m_host; }
diff --git a/libp2p/Common.h b/libp2p/Common.h
index a5f7e5d84..bb1b1e2e0 100644
--- a/libp2p/Common.h
+++ b/libp2p/Common.h
@@ -24,6 +24,8 @@
 #pragma once
 
 #include <string>
+#include <set>
+#include <vector>
 #include <boost/asio.hpp>
 #include <boost/asio/ip/tcp.hpp>
 #include <chrono>
@@ -88,13 +90,17 @@ enum DisconnectReason
 /// @returns the string form of the given disconnection reason.
 std::string reasonOf(DisconnectReason _r);
 
+typedef std::pair<std::string, u256> CapDesc;
+typedef std::set<CapDesc> CapDescSet;
+typedef std::vector<CapDesc> CapDescs;
+
 struct PeerInfo
 {
 	std::string clientVersion;
 	std::string host;
 	unsigned short port;
 	std::chrono::steady_clock::duration lastPing;
-	std::set<std::string> caps;
+	std::set<CapDesc> caps;
 	unsigned socket;
 	std::map<std::string, std::string> notes;
 };
diff --git a/libp2p/Host.cpp b/libp2p/Host.cpp
index 43758f0f5..d13cbf4f9 100644
--- a/libp2p/Host.cpp
+++ b/libp2p/Host.cpp
@@ -38,6 +38,7 @@
 #include <libdevcore/Common.h>
 #include <libethcore/Exceptions.h>
 #include "Session.h"
+#include "Common.h"
 #include "Capability.h"
 #include "UPnP.h"
 using namespace std;
@@ -145,7 +146,7 @@ unsigned Host::protocolVersion() const
 	return 0;
 }
 
-void Host::registerPeer(std::shared_ptr<Session> _s, vector<string> const& _caps)
+void Host::registerPeer(std::shared_ptr<Session> _s, CapDescs const& _caps)
 {
 	{
 		Guard l(x_peers);
diff --git a/libp2p/Host.h b/libp2p/Host.h
index f5f2f9e97..b4ba9c2d4 100644
--- a/libp2p/Host.h
+++ b/libp2p/Host.h
@@ -31,6 +31,7 @@
 #include <libdevcore/Guards.h>
 #include <libdevcore/Worker.h>
 #include "HostCapability.h"
+#include "Common.h"
 namespace ba = boost::asio;
 namespace bi = boost::asio::ip;
 
@@ -75,11 +76,11 @@ public:
 	unsigned protocolVersion() const;
 
 	/// Register a peer-capability; all new peer connections will have this capability.
-	template <class T> std::shared_ptr<T> registerCapability(T* _t) { _t->m_host = this; auto ret = std::shared_ptr<T>(_t); m_capabilities[T::staticName()] = ret; return ret; }
+	template <class T> std::shared_ptr<T> registerCapability(T* _t) { _t->m_host = this; auto ret = std::shared_ptr<T>(_t); m_capabilities[std::make_pair(T::staticName(), T::staticVersion())] = ret; return ret; }
 
-	bool haveCapability(std::string const& _name) const { return m_capabilities.count(_name) != 0; }
-	std::vector<std::string> caps() const { std::vector<std::string> ret; for (auto const& i: m_capabilities) ret.push_back(i.first); return ret; }
-	template <class T> std::shared_ptr<T> cap() const { try { return std::static_pointer_cast<T>(m_capabilities.at(T::staticName())); } catch (...) { return nullptr; } }
+	bool haveCapability(CapDesc const& _name) const { return m_capabilities.count(_name) != 0; }
+	CapDescs caps() const { CapDescs ret; for (auto const& i: m_capabilities) ret.push_back(i.first); return ret; }
+	template <class T> std::shared_ptr<T> cap() const { try { return std::static_pointer_cast<T>(m_capabilities.at(std::make_pair(T::staticName(), T::staticVersion()))); } catch (...) { return nullptr; } }
 
 	/// Connect to a peer explicitly.
 	static std::string pocHost();
@@ -118,7 +119,7 @@ public:
 
 	h512 id() const { return m_id; }
 
-	void registerPeer(std::shared_ptr<Session> _s, std::vector<std::string> const& _caps);
+	void registerPeer(std::shared_ptr<Session> _s, CapDescs const& _caps);
 
 private:
 	/// Called when the session has provided us with a new peer we can connect to.
@@ -166,7 +167,7 @@ private:
 	std::vector<bi::address_v4> m_addresses;
 	std::vector<bi::address_v4> m_peerAddresses;
 
-	std::map<std::string, std::shared_ptr<HostCapabilityFace>> m_capabilities;
+	std::map<CapDesc, std::shared_ptr<HostCapabilityFace>> m_capabilities;
 
 	bool m_accepting = false;
 };
diff --git a/libp2p/HostCapability.cpp b/libp2p/HostCapability.cpp
index a3a47cd5c..2f295afd0 100644
--- a/libp2p/HostCapability.cpp
+++ b/libp2p/HostCapability.cpp
@@ -38,7 +38,7 @@ std::vector<std::shared_ptr<Session> > HostCapabilityFace::peers() const
 	std::vector<std::shared_ptr<Session> > ret;
 	for (auto const& i: m_host->m_peers)
 		if (std::shared_ptr<Session> p = i.second.lock())
-			if (p->m_capabilities.count(name()))
+			if (p->m_capabilities.count(capDesc()))
 				ret.push_back(p);
 	return ret;
 }
diff --git a/libp2p/HostCapability.h b/libp2p/HostCapability.h
index 1c532788b..f07900034 100644
--- a/libp2p/HostCapability.h
+++ b/libp2p/HostCapability.h
@@ -47,6 +47,8 @@ public:
 
 protected:
 	virtual std::string name() const = 0;
+	virtual u256 version() const = 0;
+	CapDesc capDesc() const { return std::make_pair(name(), version()); }
 	virtual Capability* newPeerCapability(Session* _s) = 0;
 
 	virtual void onStarting() {}
@@ -66,9 +68,11 @@ public:
 	virtual ~HostCapability() {}
 
 	static std::string staticName() { return PeerCap::name(); }
+	static u256 staticVersion() { return PeerCap::version(); }
 
 protected:
 	virtual std::string name() const { return PeerCap::name(); }
+	virtual u256 version() const { return PeerCap::version(); }
 	virtual Capability* newPeerCapability(Session* _s) { return new PeerCap(_s, this); }
 };
 
diff --git a/libp2p/Session.cpp b/libp2p/Session.cpp
index c50990476..71780ff6b 100644
--- a/libp2p/Session.cpp
+++ b/libp2p/Session.cpp
@@ -40,7 +40,7 @@ Session::Session(Host* _s, bi::tcp::socket _socket, bi::address _peerAddress, un
 {
 	m_disconnect = std::chrono::steady_clock::time_point::max();
 	m_connect = std::chrono::steady_clock::now();
-	m_info = PeerInfo({"?", _peerAddress.to_string(), m_listenPort, std::chrono::steady_clock::duration(0), set<string>(), 0, map<string, string>()});
+	m_info = PeerInfo({"?", _peerAddress.to_string(), m_listenPort, std::chrono::steady_clock::duration(0), CapDescSet(), 0, map<string, string>()});
 }
 
 Session::~Session()
@@ -78,7 +78,7 @@ bool Session::interpret(RLP const& _r)
 	{
 		m_protocolVersion = _r[1].toInt<unsigned>();
 		auto clientVersion = _r[2].toString();
-		auto caps = _r[3].toVector<string>();
+		auto caps = _r[3].toVector<CapDesc>();
 		m_listenPort = _r[4].toInt<unsigned short>();
 		m_id = _r[5].toHash<h512>();
 
@@ -102,7 +102,7 @@ bool Session::interpret(RLP const& _r)
 			return false;
 		}
 		try
-			{ m_info = PeerInfo({clientVersion, m_socket.remote_endpoint().address().to_string(), m_listenPort, std::chrono::steady_clock::duration(), _r[3].toSet<string>(), (unsigned)m_socket.native_handle(), map<string, string>() }); }
+			{ m_info = PeerInfo({clientVersion, m_socket.remote_endpoint().address().to_string(), m_listenPort, std::chrono::steady_clock::duration(), _r[3].toSet<CapDesc>(), (unsigned)m_socket.native_handle(), map<string, string>() }); }
 		catch (...)
 		{
 			disconnect(BadProtocol);
diff --git a/libp2p/Session.h b/libp2p/Session.h
index 934e548d4..9b04154ee 100644
--- a/libp2p/Session.h
+++ b/libp2p/Session.h
@@ -62,7 +62,7 @@ public:
 	bi::tcp::endpoint endpoint() const;	///< for other peers to connect to.
 
 	template <class PeerCap>
-	std::shared_ptr<PeerCap> cap() const { try { return std::static_pointer_cast<PeerCap>(m_capabilities.at(PeerCap::name())); } catch (...) { return nullptr; } }
+	std::shared_ptr<PeerCap> cap() const { try { return std::static_pointer_cast<PeerCap>(m_capabilities.at(std::make_pair(PeerCap::name(), PeerCap::version()))); } catch (...) { return nullptr; } }
 
 	static RLPStream& prep(RLPStream& _s);
 	void sealAndSend(RLPStream& _s);
@@ -108,7 +108,7 @@ private:
 
 	unsigned m_rating;
 
-	std::map<std::string, std::shared_ptr<Capability>> m_capabilities;
+	std::map<CapDesc, std::shared_ptr<Capability>> m_capabilities;
 
 	bool m_willBeDeleted = false;			///< True if we already posted a deleter on the strand.
 };
diff --git a/libwhisper/WhisperPeer.h b/libwhisper/WhisperPeer.h
index b3fe2701b..ae20cae68 100644
--- a/libwhisper/WhisperPeer.h
+++ b/libwhisper/WhisperPeer.h
@@ -53,6 +53,7 @@ public:
 	virtual ~WhisperPeer();
 
 	static std::string name() { return "shh"; }
+	static u256 version() { return 1; }
 
 	WhisperHost* host() const;