diff --git a/grive/src/main.cc b/grive/src/main.cc
index b017558..cec9020 100644
--- a/grive/src/main.cc
+++ b/grive/src/main.cc
@@ -83,6 +83,7 @@ int Main( int argc, char **argv )
 		( "auth,a",		"Request authorization token" )
 		( "verbose,V",	"Verbose mode. Enable more messages than normal.")
 		( "log-xml",	"Log more HTTP responses as XML for debugging.")
+		( "new-rev",	"Create new revisions in server for updated files.")
 		( "debug,d",	"Enable debug level messages. Implies -v.")
 		( "log,l",		po::value<std::string>(), "Set log output filename." )
 		( "force,f",	"Force grive to always download a file from Google Drive "
@@ -149,6 +150,7 @@ int Main( int argc, char **argv )
 	}
 	
 	options.Add( "log-xml", Json(vm.count("log-xml") > 0) ) ;
+	options.Add( "new-rev", Json(vm.count("new-rev") > 0) ) ;
 	
 	if ( vm.count( "debug" ) )
 	{
diff --git a/libgrive/src/drive/Drive.cc b/libgrive/src/drive/Drive.cc
index 5151369..5595fcc 100644
--- a/libgrive/src/drive/Drive.cc
+++ b/libgrive/src/drive/Drive.cc
@@ -26,7 +26,6 @@
 #include "http/Agent.hh"
 #include "http/ResponseLog.hh"
 #include "http/XmlResponse.hh"
-#include "protocol/Json.hh"
 #include "util/Destroy.hh"
 #include "util/log/Log.hh"
 #include "xml/Node.hh"
@@ -55,7 +54,7 @@ namespace
 Drive::Drive( http::Agent *http, const Json& options ) :
 	m_http		( http ),
 	m_state		( state_file, options ),
-	m_log_xml	( options["log-xml"].Bool() )
+	m_options	( options )
 {
 	assert( m_http != 0 ) ;
 }
@@ -137,7 +136,7 @@ void Drive::DetectChanges()
 
 	Log( "Reading remote server file list", log::info ) ;
 	Feed feed ;
-	if ( m_log_xml )
+	if ( m_options["log-xml"].Bool() )
 		feed.EnableLog( "/tmp/file", ".xml" ) ;
 	
 	feed.Start( m_http, http::Header(), feed_base + "?showfolders=true&showroot=true" ) ;
@@ -158,7 +157,7 @@ void Drive::DetectChanges()
 	{
 		Log( "Detecting changes from last sync", log::info ) ;
 		Feed changes ;
-		if ( m_log_xml )
+		if ( m_options["log-xml"].Bool() )
 			feed.EnableLog( "/tmp/changes", ".xml" ) ;
 			
 		feed.Start( m_http, http::Header(), ChangesFeed(prev_stamp+1) ) ;
@@ -172,7 +171,7 @@ void Drive::DetectChanges()
 void Drive::Update()
 {
 	Log( "Synchronizing files", log::info ) ;
-	m_state.Sync( m_http ) ;
+	m_state.Sync( m_http, m_options ) ;
 	
 	UpdateChangeStamp( ) ;
 }
@@ -180,7 +179,7 @@ void Drive::Update()
 void Drive::DryRun()
 {
 	Log( "Synchronizing files (dry-run)", log::info ) ;
-	m_state.Sync( 0 ) ;
+	m_state.Sync( 0, m_options ) ;
 }
 
 void Drive::UpdateChangeStamp( )
diff --git a/libgrive/src/drive/Drive.hh b/libgrive/src/drive/Drive.hh
index 11830b5..3409953 100644
--- a/libgrive/src/drive/Drive.hh
+++ b/libgrive/src/drive/Drive.hh
@@ -22,6 +22,7 @@
 #include "State.hh"
 
 #include "http/Header.hh"
+#include "protocol/Json.hh"
 #include "util/Exception.hh"
 
 #include <string>
@@ -35,7 +36,6 @@ namespace http
 }
 
 class Entry ;
-class Json ;
 
 class Drive
 {
@@ -61,7 +61,7 @@ private :
 	std::string		m_resume_link ;
 	State			m_state ;
 	
-	bool			m_log_xml ;
+	Json			m_options ;
 } ;
 
 } // end of namespace
diff --git a/libgrive/src/drive/Resource.cc b/libgrive/src/drive/Resource.cc
index c044abc..f63f99e 100644
--- a/libgrive/src/drive/Resource.cc
+++ b/libgrive/src/drive/Resource.cc
@@ -365,23 +365,24 @@ Resource* Resource::FindChild( const std::string& name )
 }
 
 // try to change the state to "sync"
-void Resource::Sync( http::Agent *http, DateTime& sync_time )
+void Resource::Sync( http::Agent *http, DateTime& sync_time, const Json& options )
 {
 	assert( m_state != unknown ) ;
 	assert( !IsRoot() || m_state == sync ) ;	// root folder is already synced
 	
-  SyncSelf( http ) ;
-  // we want the server sync time, so we will take the server time of the last file uploaded to store as the sync time
-  // m_mtime is updated to server modified time when the file is uploaded
-  sync_time = std::max(sync_time, m_mtime);
+	SyncSelf( http, options ) ;
+	
+	// we want the server sync time, so we will take the server time of the last file uploaded to store as the sync time
+	// m_mtime is updated to server modified time when the file is uploaded
+	sync_time = std::max(sync_time, m_mtime);
 	
 	// if myself is deleted, no need to do the childrens
 	if ( m_state != local_deleted && m_state != remote_deleted )
 		std::for_each( m_child.begin(), m_child.end(),
-			boost::bind( &Resource::Sync, _1, http, boost::ref(sync_time) ) ) ;
+			boost::bind( &Resource::Sync, _1, http, boost::ref(sync_time), options ) ) ;
 }
 
-void Resource::SyncSelf( http::Agent* http )
+void Resource::SyncSelf( http::Agent* http, const Json& options )
 {
 	assert( !IsRoot() || m_state == sync ) ;	// root is always sync
 	assert( IsRoot() || http == 0 || fs::is_directory( m_parent->Path() ) ) ;
@@ -407,7 +408,7 @@ void Resource::SyncSelf( http::Agent* http )
 	
 	case local_changed :
 		Log( "sync %1% changed in local. uploading", path, log::info ) ;
-		if ( http != 0 && EditContent( http ) )
+		if ( http != 0 && EditContent( http, options["new-rev"].Bool() ) )
 			m_state = sync ;
 		break ;
 	
@@ -520,7 +521,7 @@ void Resource::Download( http::Agent* http, const fs::path& file ) const
 	}
 }
 
-bool Resource::EditContent( http::Agent* http )
+bool Resource::EditContent( http::Agent* http, bool new_rev )
 {
 	assert( http != 0 ) ;
 	assert( m_parent != 0 ) ;
@@ -533,10 +534,10 @@ bool Resource::EditContent( http::Agent* http )
 		return false ;
 	}
 	
-	return Upload( http, m_edit, false ) ;
+	return Upload( http, m_edit + (new_rev ? "?new-revision=true" : ""), false ) ;
 }
 
-bool Resource::Create( http::Agent* http)
+bool Resource::Create( http::Agent* http )
 {
 	assert( http != 0 ) ;
 	assert( m_parent != 0 ) ;
diff --git a/libgrive/src/drive/Resource.hh b/libgrive/src/drive/Resource.hh
index b0cb2b8..8b157f7 100644
--- a/libgrive/src/drive/Resource.hh
+++ b/libgrive/src/drive/Resource.hh
@@ -35,6 +35,7 @@ namespace http
 }
 
 class Entry ;
+class Json ;
 
 /*!	\brief	A resource can be a file or a folder in the google drive
 
@@ -76,7 +77,7 @@ public :
 	void FromRemote( const Entry& remote, const DateTime& last_sync ) ;
 	void FromLocal( const DateTime& last_sync ) ;
 	
-	void Sync( http::Agent* http, DateTime& sync_time ) ;
+	void Sync( http::Agent* http, DateTime& sync_time, const Json& options ) ;
 
 	// children access
 	iterator begin() const ;
@@ -124,7 +125,7 @@ private :
 	void SetState( State new_state ) ;
 
 	void Download( http::Agent* http, const fs::path& file ) const ;
-	bool EditContent( http::Agent* http ) ;
+	bool EditContent( http::Agent* http, bool new_rev ) ;
 	bool Create( http::Agent* http ) ;
 	bool Upload( http::Agent* http, const std::string& link, bool post ) ;
 	
@@ -135,7 +136,7 @@ private :
 	void DeleteRemote( http::Agent* http ) ;
 	
 	void AssignIDs( const Entry& remote ) ;
-	void SyncSelf( http::Agent* http ) ;
+	void SyncSelf( http::Agent* http, const Json& options ) ;
 	
 private :
 	std::string				m_name ;
diff --git a/libgrive/src/drive/State.cc b/libgrive/src/drive/State.cc
index afab842..8825f0c 100644
--- a/libgrive/src/drive/State.cc
+++ b/libgrive/src/drive/State.cc
@@ -261,7 +261,7 @@ void State::Write( const fs::path& filename ) const
 	fs << result ;
 }
 
-void State::Sync( http::Agent *http )
+void State::Sync( http::Agent *http, const Json& options )
 {
 	// set the last sync time from the time returned by the server for the last file synced
 	// if the sync time hasn't changed (i.e. now files have been uploaded)
@@ -271,7 +271,8 @@ void State::Sync( http::Agent *http )
 	// TODO - WARNING - do we use the last sync time to compare to client file times
 	// need to check if this introduces a new problem
  	DateTime last_sync_time = m_last_sync;
-	m_res.Root()->Sync( http, last_sync_time ) ;
+	m_res.Root()->Sync( http, last_sync_time, options ) ;
+	
   	if ( last_sync_time == m_last_sync )
   	{
 		Trace( "nothing changed? %1%", m_last_sync ) ;
diff --git a/libgrive/src/drive/State.hh b/libgrive/src/drive/State.hh
index cd0590d..9ddd435 100644
--- a/libgrive/src/drive/State.hh
+++ b/libgrive/src/drive/State.hh
@@ -57,7 +57,7 @@ public :
 	Resource* FindByID( const std::string& id ) ;
 	Resource* Find( const fs::path& path ) ;
 
-	void Sync( http::Agent *http ) ;
+	void Sync( http::Agent *http, const Json& options ) ;
 	
 	iterator begin() ;
 	iterator end() ;
diff --git a/libgrive/src/http/CurlAgent.cc b/libgrive/src/http/CurlAgent.cc
index 640e1eb..09bedee 100644
--- a/libgrive/src/http/CurlAgent.cc
+++ b/libgrive/src/http/CurlAgent.cc
@@ -150,12 +150,15 @@ long CurlAgent::ExecCurl(
 	dest->Clear() ;
 	CURLcode curl_code = ::curl_easy_perform(curl);
 
+	// get the HTTTP response code
 	long http_code = 0;
-	::curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
-
+	::curl_easy_getinfo(curl,	CURLINFO_RESPONSE_CODE, &http_code);
 	Trace( "HTTP response %1%", http_code ) ;
-	::curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, 	0 ) ;
 	
+	// reset the curl buffer to prevent it from touch our "error" buffer
+	::curl_easy_setopt(curl,	CURLOPT_ERRORBUFFER, 	0 ) ;
+	
+	// only throw for libcurl errors
 	if ( curl_code != CURLE_OK )
 	{
 		BOOST_THROW_EXCEPTION(